Premenstrual symptoms in young adults born preterm at very low birth weight - from the Helsinki Study of Very Low Birth Weight Adults
© Mustaniemi et al; licensee BioMed Central Ltd. 2011
Received: 27 December 2010
Accepted: 3 June 2011
Published: 3 June 2011
Clinically significant premenstrual symptoms are common among young women. Premenstrual syndrome (PMS) is characterized by emotional, behavioural and physical symptoms that consistently occur during the luteal phase of the menstrual cycle. Premenstrual dysphoric disorder (PMDD) is a severe form of PMS. Individual variation in stress responsiveness may be involved in the pathophysiology of premenstrual symptoms. Preterm birth at very low birth weight (VLBW, < 1500g) has a multitude of consequences that extend to adult life, including altered stress responsiveness which could affect the prevalence of premenstrual symptoms.
In this cohort study, we compared 75 VLBW women with 95 women born at term (mean age 22.5). We used a standardized retrospective questionnaire assessing the presence and severity of a variety of symptoms before and after menses. The symptom scores were used both as continuous and as dichotomized variables, with cutoffs based on DSM-IV criteria for PMDD and ACOG criteria for PMS, except prospective daily ratings could not be used. We used multiple linear and logistic regression to adjust for confounders.
There was no difference in the continuous symptom score before menses (mean difference VLBW-term -18.3%, 95% confidence interval -37.9 to 7.5%) or after menses. The prevalence of premenstrual symptoms causing severe impairment to daily life was 13.3% for VLBW women and 14.7% for control women. For PMDD, it was 8.0% and 4.2%, and for PMS, 12.0% and 11.6%, respectively. These differences were not statistically significant (p > 0.1).
Our findings suggest that the severity of premenstrual symptoms and the prevalence of PMDD and PMS among young women born preterm at VLBW is not higher than among those born at term.
It is now widely accepted that several common adult diseases have their origins during the fetal period and infancy. Although there is some heterogeneity between studies, adults born with low birth weight show increased risk of cardiovascular disease [1, 2], type 2 diabetes  and depression . Recent studies by us [5, 6] and others [7–9] suggest particularly high levels of risk factors for these disorders in young adults born preterm at very low birth weight (VLBW, < 1500g).
Mechanisms that link early life events with adult disease remain poorly known. Early life programming of endocrine and other physiological responses to stress may have an important role to play . There is emerging evidence that preterm birth may affect stress responsiveness in later life, in particular the function of the hypothalamic-pituitary-adrenal (HPA) axis [10–12].
Up to 30% of women of reproductive age report premenstrual symptoms severe enough to warrant diagnosis of premenstrual syndrome (PMS) [13, 14]. PMS is characterized by cyclic and recurrent emotional, behavioural and / or physical symptoms which occur during the late luteal phase, remit within days of menses and are associated with suffering and impairment premestrually . Premenstrual dysphoric disorder (PMDD) is a severe form of PMS characterized by mood, behavioural and cognitive complaints which seriously interfere with relationships, social activities and work. The estimated prevalence of PMDD is 3-8% . The burden of PMDD during the late luteal phase may reach the same level as that of major dysphoric disorders.
Premenstrual disorders and symptoms are complex phenomena which despite decades of research remain poorly understood. Hormonal systems, in particular the HPA axis, are believed to be involved [16–18], and the prevailing view is that women with PMS are more sensitive to essentially normal hormonal swifts. Important determinants predicting how a woman will experience premenstrual symptoms are also believed to include individual differences in response to stress and adverse events earlier in life [19, 20]. While lifecourse studies have thus far focused on events such as sexual abuse , adverse events could as well be biological and occur early in life: infants born preterm at VLBW experience after birth a period of immaturity-associated illness characterised by inadequate nutrition, impaired growth and deprivation from normal parental attachment, and the consequences of this period on hormonal function and stress responsiveness extend to adult life. With this background, we hypothesized that young adult women born at very low birth weight have a higher degree of premenstrual symptoms than their peers born at term.
The participants were a subgroup of the Helsinki Study of Very Low Birth Weight Adults, which has been described in detail [5, 6]. Briefly, the original study cohort comprised 335 consecutive VLBW (< 1500g) infants (of whom 178 were women) who were born between January 1978 and December 1985 and who were discharged alive from the neonatal intensive care unit of Children's Hospital at the Helsinki University Central Hospital in Finland. For each VLBW survivor, the next term born (gestational age > 37 weeks) singleton infant of the same sex, and not small for gestational age (SGA, birth weight < -2SD) was selected to act as control (n = 367, of whom 201 women). We invited 255 VLBW (139 women) and 314 term (169 women) participants who lived in the greater Helsinki area to a clinical examination, and 166 (95 women, 68% of those invited) and 172 (103 women, 61%) agreed to participate.
Characteristics of the women
(N = 86)
(N = 101)
P Value a
Birth weight, g
Gestational age, wk
Standard deviation score for birth weight
SGAb, n (%)
Maternal preeclampsiac, n (%)
Twin, n (%)
Triplet, n (%)
Maternal smoking during pregnancy, n (%)
Highest education of either parentd, n (%)
Daily smoking, n (%)
Regular menstrual cyclee, n (%)
Duration of menorrheaf, d
Hormonal contraception, n (%)
Hormone releasing intrauterine device
Other or unknown type of hormonal contraception
Treatment for mental disorders during previous three monthsg, n(%)
Anxiety or panic disorder
We used a validated, widely used questionnaire to assess self-reports of Menstrually-Related Disorders . The assessment retrospectively enquires symptoms during the last three menstrual cycles, for each cycle during the week before menses (premenstrual period) and the week after menses. The 21 symptom items concern depressive symptoms, irritability, affective lability, anxiety, change in sleep, change in appetite (e.g. food cravings), decreased interest in activities, difficulty concentrating, feeling out of control or overwhelmed, lack of energy and physical symptoms such as breast tenderness and swelling.
The participant was asked to score the severity of each symptom from 1 to 5 (1 = minimal and 5 = extremely severe). As continuous outcome variables we used the sum of these scores before and after menses, plus the difference of these scores. In addition, the questionnaire includes three questions of the effect and burden of these symptoms to work, social relationships and daily activity, which were assessed separately.
As dichotomous outcomes, we used a) the score for each individual question dichotomized at 3 or more to indicate significant severe symptoms; b) whether the participant fulfils the DSM-IV-based criteria of PMDD ; c) whether she fulfils the ACOG (American College of Obstetricians and Gynecologists)  criteria for PMS, with the exception that we could not apply prospective daily ratings within this protocol. DSM-IV PMDD criteria presume a person to have at least five premenstrual symptoms (including at least one major dysphoric symptom: irritability, depressed mood, affective lability or anxiety) which seriously interfere with work, social activities and relationships. In addition, we assessed the proportion of women who reported at least one dysphoric symptom, which substantially impacts their life during the premenstrual period. ACOG PMS criteria require that a person has at least one affective (depression, angry outbursts, irritability, anxiety, confusion, social withdrawal) or somatic (breast tenderness, abdominal bloating, headache, swelling of extremities) symptom premenstrually during each of three prior menstrual cycles.
Birth weight, gestational age and other perinatal and maternal data (smoking during pregnancy, preeclampsia) were collected from hospital records. The participants completed a wide range of questionnaires concerning their medical history, use of medications, current educational level, smoking and parental education (the highest level of current education achieved by either parent, categorized into four levels). Weight and height were measured and body mass index (BMI) was calculated. Questionnaires were completed in conjunction with a clinical examination. The study protocol was approved by the Ethics Committee for Children and Adolescents Diseases and Psychiatry at Helsinki and Uusimaa Hospital District. Each participant gave a written informed consent.
Data analytic strategy
The study was powered with regard to differences in symptom score as continuous variables. With 80% power and alpha level of 0.05, 75 VLBW and 95 control participants allow us to detect or exclude a 0.44 SD difference. With 90% power and alpha 0.01, the corresponding difference is 0.60 SD. A total symptom score was calculated as the sum of the score for each specific symptom, with separate scores before and after menses. The total score after menses was subtracted from the total score before menses to evaluate the difference between the premenstrual period and time after menstruation. These scores were used as outcomes (with the total scores log-transformed to attain normality) together with the dichotomous outcome variables, calculated as described in the Procedures section. Differences between VLBW young women and term controls were examined by Student's t-test for continuous variables, Pearson's chi square test for dichotomous variables and multiple linear and logistic regressions to adjust for the following covariates: age, parental education, BMI, the current use of hormonal contraception, own current smoking and maternal smoking during pregnancy. Comparisons of participating women with nonparticipants regarding the duration of mechanical ventilation, the duration of oxygen administration and age at discharge were analyzed by means of the Mann-Whitney U test.
Gestational age of prematurely born VLBW participants ranged from 25.0 to 35.6 weeks and birth weights from 620 to 1490 g. The control participants' gestational ages ranged from 37.0 to 42.9 weeks and birth weights from 2560 to 4900 g. 24.4% of VLBW participants were born small for gestational age. The prevalence of maternal preeclampsia was 22.0% in the VLBW group and 5.9% in the control group (p = 0.001). 19.8% of VLBW participants were born from multiple pregnancies. At examination, the VLBW women were shorter (p = 0.02) and lighter (p = 0.001) than those born at term, but the groups were similar regarding the other baseline characteristics (Table 1).
Premenstrual symptom scores among young women born at VLBW and their counterparts born at term
N = 75
N = 95
Total score before menses
-19.4% (-38.2 to 5.0%)
-18.3% (-37.9 to 7.5%)
Total score after menses
-17.7% (-41.8 to 16.3%)
-14.7% (-40.5 to 22.5%)
Difference between total score before and after menses
-0.56 (-2.96 to 1.85)
-0.71 (-3.24 to 1.83)
Odds ratio (95% CI) b
Odds ratio (95% CI) c
1.97 (0.53 to 7.25)
1.82 (0.47 to 7.07)
0.97 (0.34 to 2.76)
0.99 (0.33 to 2.93)
1.03 (0.40 to 2.65)
1.00 (0.37 to 2.67)
PMS symptoms seriously interfere with work, social activities, relationships
0.88 (0.37 to 2.12)
0.89 (0.35 to 2.23)
Presence of each premenstrual symptom before menses
Depressed mood or hopelessness
2.71 (0.78 to 9.39)
2.24 (0.61 to 8.27)
Tension or anxiety
0.80 (0.39 to 1.64)
0.86 (0.40 to 1.87)
0.68 (0.33 to 1.39)
0.56 (0.26 to 1.19)
0.62 (0.29 to 1.32)
0.61 (0.28 to 1.36)
Decrease interest in activities
1.56 (0.45 to 5.43)
1.51 (0.41 to 5.53)
1.57 (0.45 to 5.47)
1.59 (0.43 to 5.84)
Lack of energy
0.77 (0.28 to 2.10)
0.82 (0.29 to 2.34)
Change in appetite, e.g., food cravings
1.44 (0.67 to 3.09)
1.34 (0.60 to 2.99)
Change in sleep
1.13 (0.41 to 3.10)
1.00 (0.35 to 2.91)
Feeling out of control or overwhelmed
0.75 (0.17 to 3.24)
0.90 (0.19 to 4.23)
Other physical symptoms, e.g., breast tenderness,
0.72 (0.37 to 1.41)
0.68 (0.34 to 1.38)
The prevalence of PMDD was 8.0% in the VLBW group and 4.2% in the controls, and the prevalence of PMS was 12.0% in the VLBW group and 11.6% in the controls. The most prevalent symptoms in both groups were affective lability, tension or anxiety, irritability and various physical symptoms. In addition, 9.3% of VLBW and 9.5% of term born participants reported at least one dysphoric symptom which substantially impacts their life during the premenstrual period. 13.3% of VLBW participants and 14.7% of controls reported that premenstrual symptoms seriously interfere with functioning at work, or with family and social relationships. As the odds ratios in Table 2 demonstrate, none of these differences was statistically significant. We also compared the prevalence of each symptom separately; again there were no statistically significant differences.
To assess possible associations with perinatal and neonatal conditions, we performed a range of analyses within the VLBW group. We compared VLBW women born SGA with VLBW women born AGA (appropriate for gestational age); those exposed to maternal preeclampsia with those not exposed; and those who developed bronchopulmonary dysplasia with those who did not. There were no differences in the total symptom scores and in the prevalence of PMDD or PMS. Neither were these outcomes associated with the duration of mechanical ventilation, the duration of oxygen administration and age at discharge.
As compared with non-participating women (= women who were invited to the clinical examination but who did not complete the premenstrual symptoms questionnaire), women who participated in the present study have similar baseline characteristics including means of birth weight (SD), gestational age, the duration of mechanical ventilation, the duration of oxygen administration and age at discharge; and prevalences of SGA, maternal preeclampsia, bronchopulmonary dysplasia and cerebral palsy diagnosed at 15 months of age (p values > 0.089).
As in our previous publications based on the same cohort [5, 6], we reanalyzed the data after the exclusion of 10 participants with cerebral palsy (n = 8) or blindness (n = 2). The results were similar. An additional reanalysis was made after including the 17 participants who had originally been excluded because of a comorbid mental disorder. Again, the results were little changed.
We hypothesized that young adult women born at VLBW have a higher degree of premenstrual symptoms than their peers born at term. Although we used a detailed and widely used symptoms score questionnaire  which is intended to detect even subtle differences below the threshold of a clinically defined disorder, we could find no differences between the VLBW and control women by any applied analytical method with or without adjustment for covariates such as body size, socio-economic status, smoking and use of hormonal contraception. Although our study was not powered to detect small differences in clinical disorders, the prevalences of PMDD (8.0% in the VLBW and 4.2% in the control group) and PMS (12.0% in VLBW, 11.6% in controls) were consistent with previous reports [15, 17] and any substantial excess of these disorders in adult women born at VLBW is unlikely.
Premenstrual symptoms and syndromes may be clinically relevant and cause serious impairment even when DSM-IV criteria are not met . These symptoms cause severe impairment in work, social activities and relationships among a significant group of young women. In the current study, the percentages of women reporting impairment were 13.3% in the VLBW group and 14.7% in the control group. This is in accordance with estimated earlier percentages which have varied between 13-18% .
With the exception a few studies focusing upon HPA axis, there are little published data on the effect of preterm birth on hormonal axes including the hypothalamic-pituitary-gonadal (HPG) axis. The little data that exist suggest that both girls and boys born at VLBW have an earlier age at pubertal growth spurt than those born at term . Contrary to this, large register studies suggest lower rates of reproduction [26, 27] in women and men born severely preterm. This may, however, be due to personality traits leading to delays of starting romantic relationships  rather than differences in gonadal endocrine function which to our knowledge has not been studied.
As to the individual differences in physiological stress responsiveness, most studies have focused on the HPA axis, but published results are not consistent. In a study of 36 participants aged 8-14 years, Buske-Kirschbaum et al. (2007) reported higher morning cortisol levels in former preterm children but found no difference in HPA axis response to psychosocial stress. Preliminary findings from a subgroup of women and men (53 VLBW and 42 term) from our study cohort suggest decreased HPA axis responsiveness to stress . Nevertheless, several observations may support the role of normal variation in HPA axis function in the pathophysiology of PMS. For example, cortisol levels before menstruation were lower in women who suffer from depressive symptoms premenstrually . In another study women with PMS failed to show the normal increased HPA axis response to exercise during the luteal phase and showed an abnormal reaction of HPA axis to progesterone . Our findings suggest that differences in hormonal functions and physiological stress responsiveness between women born at VLBW and those born at term, if they exist, are not reflected in the prevalence of reported premenstrual symptoms.
The main limitations of the study were the relatively small study population, resulting in limited power especially in sub-group analyses. However, it is of note that our sample size was larger than in most previous endocrine- and stress-related studies in people born preterm [11, 12]. Moreover, as prospective daily ratings were not possible to realize, we obtained a retrospective report of the most recent 3 menstrual cycles. Retrospective self-report is not as reliable a method to reflect daily symptom experience as are prospective daily ratings, which also are the standard requirement for the accurate diagnosis of PMS or PMDD . Therefore our finding of no difference in the prevalence of reported PMDD and PMS should be treated with caution.
In conclusion, premenstrual symptoms are common and cause significant impairment in the daily life of many young women. However, women born at VLBW seem not to suffer from premenstrual symptoms more than their peers born at term.
Acknowledgements and Funding
The authors gratefully acknowledge all participants of the study; research nurses Anne Kaski, Paula Nyholm, Hilkka Puttonen, and Marita Suni; and Sigrid Rostén for data management.
The study was supported by grants from the Academy of Finland, the Biomedicum Helsinki Foundation, the Finnish Concordia Foundation, The Finnish Foundation for Diabetes Research, Finnish Medical Societies (Duodecim and Finska Läkaresällskapet), the Finnish Medical Society Duodecim (Oulu Division), the Finnish Foundation for Pediatric Research, the Finnish Special Governmental Subsidary for Health Sciences, the Jalmari and Rauha Ahokas Foundation, the Juho Vainio Foundation, the Novo Nordisk Foundation, the Päivikki and Sakari Sohlberg Foundation, the Finnish National Graduate School of Public Health, the Pediatric Graduate School and the Clinical Graduate School in Paediatrics and Obstetrics/Gynaecology at University of Helsinki, the Research Foundation for the Orion Corporation, the Signe and Ane Gyllenberg Foundation, the Sigrid Jusélius Foundatiom, and the Yrjö Jahnsson Foundation. The funding agencies had no role in study design, in the collection, analysis and interpretation of the data; in the writing of the report; and in the decision to submit the paper for publication.
- Barker DJ, Osmond C, Forsen TJ, Kajantie E, Eriksson JG: Trajectories of growth among children who have coronary events as adults. N Engl J Med. 2005, 353 (17): 1802-1809. 10.1056/NEJMoa044160.View ArticlePubMedGoogle Scholar
- Huxley R, Owen CG, Whincup PH, Cook DG, Rich-Edwards J, Smith GD, Collins R: Is birth weight a risk factor for ischemic heart disease in later life?. Am J Clin Nutr. 2007, 85 (5): 1244-1250.PubMedGoogle Scholar
- Whincup PH, Kaye SJ, Owen CG, Huxley R, Cook DG, Anazawa S, Barrett-Connor E, Bhargava SK, Birgisdottir BE, Carlsson S, de Rooij SR, Dyck RF, Eriksson JG, Falkner B, Fall C, Forsen T, Grill V, Gudnason V, Hulman S, Hyppönen E, Jeffreys M, Lawlor DA, Leon DA, Minami J, Mishra G, Osmond C, Power C, Rich-Edwards JW, Roseboom TJ, Sachdev HS, Syddall H, Thorsdottir I, Vanhala M, Wadsworth M, Yarbrough DE: Birth weight and risk of type 2 diabetes: a systematic review. JAMA. 2008, 300 (24): 2886-2897. 10.1001/jama.2008.886.View ArticlePubMedGoogle Scholar
- Räikkönen K, Pesonen AK, Kajantie E, Heinonen K, Forsen T, Phillips DI, Osmond C, Barker DJ, Eriksson JG: Length of gestation and depressive symptoms at age 60 years. Br J Psychiatry. 2007, 190: 469-474. 10.1192/bjp.bp.106.022145.View ArticlePubMedGoogle Scholar
- Hovi P, Andersson S, Eriksson JG, Järvenpää AL, Strang-Karlsson S, Mäkitie O, Kajantie E: Glucose regulation in young adults with very low birth weight. N Engl J Med. 2007, 356 (20): 2053-2063. 10.1056/NEJMoa067187.View ArticlePubMedGoogle Scholar
- Räikkönen K, Pesonen AK, Heinonen K, Kajantie E, Hovi P, Järvenpää AL, Eriksson JG, Andersson S: Depression in young adults with very low birth weight: the Helsinki study of very low-birth-weight adults. Arch Gen Psychiatry. 2008, 65 (3): 290-296. 10.1001/archgenpsychiatry.2007.40.View ArticlePubMedGoogle Scholar
- Schmidt LA, Miskovic V, Boyle MH, Saigal S: Shyness and timidity in young adults who were born at extremely low birth weight. Pediatrics. 2008, 122 (1): 181-7. 10.1542/peds.2007-3747.View ArticleGoogle Scholar
- Aarnoudse-Moens CS, Weisglas-Kuperus N, van Goudoever JB, Oosterlaan J: Meta-analysis of neurobehavioral outcomes in very preterm and/or very low birth weight children. Pediatrics. 2009, 124 (2): 717-728. 10.1542/peds.2008-2816.View ArticlePubMedGoogle Scholar
- Doyle LW, Anderson PJ: Adult outcome of extremely preterm infants. Pediatrics. 2010, 126 (2): 342-351. 10.1542/peds.2010-0710.View ArticlePubMedGoogle Scholar
- Kajantie E, Räikkönen K: Early life predictors of the physiological stress response later in life. Neurosci Biobehav Rev. 2010, 35 (1): 23-32. 10.1016/j.neubiorev.2009.11.013.View ArticlePubMedGoogle Scholar
- Buske-Kirschbaum A, Krieger S, Wilkes C, Rauh W, Weiss S, Hellhammer DH: Hypothalamic-pituitary-adrenal axis function and the cellular immune response in former preterm children. J Clin Endocrinol Metab. 2007, 92 (9): 3429-3435. 10.1210/jc.2006-2223.View ArticlePubMedGoogle Scholar
- Kaseva N, Pyhälä R, Räikkönen K, Feldt K, Hovi P, Wehkalampi K, Moltchanova E, Järvenpää A, Eriksson JG, Andersson S, Kajantie E: HPAA, insulin, and glucose responses to psychosocial stress among young adults with very low birth weight [abstract]. Pediatric Acedemic Societies. 2010, Annual Meeting, Abstract 3733.333Google Scholar
- Freeman EW: Premenstrual syndrome and premenstrual dysphoric disorder: definitions and diagnosis. Psychoneuroendocrinology. 2003, 28 (Suppl 3): 25-37.View ArticlePubMedGoogle Scholar
- Halbreich U, Backstrom T, Eriksson E, O'brien S, Calil H, Ceskova E, Dennerstein L, Douki S, Freeman E, Genazzani A, Heuser I, Kadri N, Rapkin A, Steiner M, Wittchen HU, Yonkers K: Clinical diagnostic criteria for premenstrual syndrome and guidelines for their quantification for research studies. Gynecol Endocrinol. 2007, 23 (3): 123-130. 10.1080/09513590601167969.View ArticlePubMedGoogle Scholar
- Halbreich U, Borenstein J, Pearlstein T, Kahn LS: The prevalence, impairment, impact, and burden of premenstrual dysphoric disorder (PMS/PMDD). Psychoneuroendocrinology. 2003, 28 (Suppl 3): 1-23.Google Scholar
- Odber J, Cawood EH, Bancroft J: Salivary cortisol in women with and without perimenstrual mood changes. J Psychosom Res. 1998, 45 (6): 557-568. 10.1016/S0022-3999(98)00061-0.View ArticlePubMedGoogle Scholar
- Halbreich U: The etiology, biology, and evolving pathology of premenstrual syndromes. Psychoneuroendocrinology. 2003, 28 (Suppl 3): 55-99.View ArticleGoogle Scholar
- Roca CA, Schmidt PJ, Altemus M, Deuster P, Danaceau MA, Putnam K, Rubinow DR: Differential menstrual cycle regulation of hypothalamic-pituitary-adrenal axis in women with premenstrual syndrome and controls. J Clin Endocrinol Metab. 2003, 88 (7): 3057-3063. 10.1210/jc.2002-021570.View ArticlePubMedGoogle Scholar
- Walker A: Theory and methodology in premenstrual syndrome research. Soc Sci Med. 1995, 41 (6): 793-800. 10.1016/0277-9536(95)00046-A.View ArticlePubMedGoogle Scholar
- Taylor D: From "It's All in Your Head " to "Taking Back the Month": Premenstrual Syndrome (PMS) Research and the Contributionsof the Society for Menstrual Cycle Research. Sex Roles. 2006, 54: 377-391. 10.1007/s11199-006-9009-z.View ArticleGoogle Scholar
- Golding JM, Taylor DL, Menard L, King MJ: Prevalence of sexual abuse history in a sample of women seeking treatment for premenstrual syndrome. J Psychosom Obstet Gynaecol. 2000, 21 (2): 69-80. 10.3109/01674820009075612.View ArticlePubMedGoogle Scholar
- Halbreich U: The diagnosis of premenstrual syndromes and premenstrual dysphoric disorder--clinical procedures and research perspectives. Gynecol Endocrinol. 2004, 19 (6): 320-334. 10.1080/0951590400018215.View ArticlePubMedGoogle Scholar
- APA (American Psychiatric Association): Diagnostic and Statistical Manual of Mental Disorders (DSM-IV). 1994, 715-718.Google Scholar
- ACOG (American College of Obstetricians and Gynecologists): Premenstrual Syndrome. ACOG Practice Bulletin No. 2000, 15.Google Scholar
- Wehkalampi K, Hovi P, Dunkel L, Strang-Karlsson S, Järvenpää AL, Eriksson JG, Andersson S, Kajantie E: Advanced Pubertal Growth Spurt in Subjects Born Preterm: The Helsinki Study of Very Low Birth Weight Adults. J Clin Endocrinol Metab. 2011, 96 (2): 525-533. 10.1210/jc.2010-1523.View ArticlePubMedGoogle Scholar
- Moster D, Lie RT, Markestad T: Long-term medical and social consequences of preterm birth. N Engl J Med. 2008, 359 (3): 262-273. 10.1056/NEJMoa0706475.View ArticlePubMedGoogle Scholar
- Swamy GK, Ostbye T, Skjaerven R: Association of preterm birth with long-term survival, reproduction, and next-generation preterm birth. JAMA. 2008, 299 (12): 1429-1436. 10.1001/jama.299.12.1429.View ArticlePubMedGoogle Scholar
- Kajantie E, Hovi P, Räikkönen K, Pesonen AK, Heinonen K, Järvenpää AL, Eriksson JG, Strang-Karlsson S, Andersson S: Young adults with very low birth weight: leaving the parental home and sexual relationships--Helsinki Study of Very Low Birth Weight Adults. Pediatrics. 2008, 122 (1): 62-72. 10.1542/peds.2007-3858.View ArticleGoogle Scholar
- Gallant SJ, Popiel DA, Hoffman DM, Chakraborty PK, Hamilton JA: Using daily ratings to confirm premenstrual syndrome/late luteal phase dysphoric disorder. Part II. What makes a "real" difference?. Psychosom Med. 1992, 54 (2): 167-181.View ArticlePubMedGoogle Scholar
- The pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/1472-6874/11/25/prepub
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