title: First birth Caesarean section and subsequent fertility: a population-based study in the USA, 2000-2008.
abstract: OBJECTIVE
  Is first birth Caesarean delivery associated with a lower likelihood of subsequent childbearing when compared with first birth vaginal delivery?
  
  
  CONCLUSIONS
  In this study of US women whose first delivery was in 2000, those who had a Caesarean delivery were less likely to have a subsequent live birth than those who delivered vaginally.
  
  
  BACKGROUND
  Some studies have reported lower birth rates subsequent to Caesarean delivery in comparison with vaginal delivery, while other studies have reported no difference.
  
  
  METHODS
  We conducted a retrospective cohort study of 52 498 women who had a first singleton live birth in the State of Pennsylvania, USA in 2000 and were followed to the end of 2008 via Pennsylvania birth certificate records to identify subsequent live births during the 8- to 9-year follow-up period.
  
  
  METHODS
  Birth certificate records of first singleton births were linked to the hospital discharge data for each mother and newborn, and linked to all birth certificate records for each mother's subsequent deliveries which occurred in 2000 to the end of 2008. Poisson regression models were used to evaluate the association between first birth factors and whether or not there was a subsequent live birth during the follow-up period.
  
  
  RESULTS
  Over an average of 8.5 years of follow-up, 40.2% of women with a Caesarean first birth did not have a subsequent live birth, compared with 33.1% of women with a vaginal first birth (risk ratio (RR): 1.21, 95% confidence interval (CI): 1.18-1.25). Adjustment for the demographic confounders of maternal age, race, education, marital status and health insurance coverage attenuated the RR to 1.16 (95% CI: 1.13-1.19). Specific pregnancy and childbirth-related complications associated with not having a subsequent live birth included diabetes-related disorders, abnormalities of organs and soft tissues of the pelvis, fetal abnormalities, premature or prolonged rupture of membranes, hypertensive disorders, amnionitis, fetal distress and other maternal health problems. However, adjustment for the pregnancy and childbirth complications had little effect on the RR of not having a subsequent live birth (RR = 1.15, 95% CI: 1.11-1.19).
  
  
  CONCLUSIONS
  We were unable to distinguish between women who did not have a subsequent live birth and those who moved out of the state, which may have introduced a selection bias if those who had Caesarean births were more likely to emigrate than those who delivered vaginally. In addition we were unable to measure pre-pregnancy body mass index, weight gain during pregnancy and prior infertility, which would have been helpful in our efforts to reduce selection bias.
  
  
  CONCLUSIONS
  The results of this study provide further corroboration of previous studies that have reported reduced fertility subsequent to Caesarean section in comparison with vaginal delivery.
  
  
  BACKGROUND
  This study was funded by the US National Institute of Child Health and Human Development (NICHD, R01-HD052990). No competing interests are declared.
authors.affiliation: Department of Public Health Sciences, College of Medicine, Penn State University, 600 Centerview Drive, Hershey, PA 17033, USA.
authors.forename: K H
authors.initials: KH
authors.lastname: Kjerulff
authors.forename: J
authors.initials: J
authors.lastname: Zhu
authors.forename: C S
authors.initials: CS
authors.lastname: Weisman
authors.forename: C V
authors.initials: CV
authors.lastname: Ananth
mesh_terms: D000328:Adult; D001723:Birth Rate; D002585:Cesarean Section / Q000009:adverse effects*; D015331:Cohort Studies; D036861:Delivery, Obstetric; D005260:Female; D005298:Fertility; D006801:Humans; D008423:Maternal Age; D007744:Obstetric Labor Complications / Q000453:epidemiology; D010414:Pennsylvania / Q000453:epidemiology; D011247:Pregnancy; D011248:Pregnancy Complications / Q000453:epidemiology; D012189:Retrospective Studies
keywords: Caesarean section; fertility; parturition; pregnancy complications; reproduction
references.citation: Am J Epidemiol. 1988 Dec;128(6):1352-63
references.pmid: 3195572
references.citation: Fertil Steril. 1985 Apr;43(4):520-8
references.pmid: 3872816
references.citation: Am J Obstet Gynecol. 2005 Jul;193(1):169-77
references.pmid: 16021075
references.citation: Am J Obstet Gynecol. 1984 Sep 15;150(2):205-12
references.pmid: 6476041
references.citation: J Reprod Med. 1986 Jul;31(7):620-4
references.pmid: 3746793
references.citation: Hum Reprod. 2013 Jul;28(7):1943-52
references.pmid: 23644593
references.citation: Epidemiology. 2003 May;14(3):300-6
references.pmid: 12859030
references.citation: BJOG. 2006 Mar;113(3):276-83
references.pmid: 16487198
references.citation: Fertil Steril. 2006 Jan;85(1):90-5
references.pmid: 16412736
references.citation: Paediatr Perinat Epidemiol. 2004 Mar;18(2):112-9
references.pmid: 14996250
references.citation: Am J Obstet Gynecol. 1987 Aug;157(2):379-83
references.pmid: 3618689
references.citation: Am J Obstet Gynecol. 1996 May;174(5):1569-74
references.pmid: 9065131
references.citation: BJOG. 2005 Aug;112(8):1061-5
references.pmid: 16045518
references.citation: Obstet Gynecol. 2005 Apr;105(4):710-8
references.pmid: 15802395
references.citation: Biosci Trends. 2011 Aug;5(4):139-50
references.pmid: 21914948
references.citation: Obstet Gynecol. 2007 Dec;110(6):1256-63
references.pmid: 18055718
references.citation: Epidemiology. 2011 Nov;22(6):753-64
references.pmid: 20502339
references.citation: Am J Public Health. 1995 Aug;85(8 Pt 1):1143-6
references.pmid: 7625515
references.citation: Hum Reprod. 2002 Jul;17(7):1914-7
references.pmid: 12093860
references.citation: Matern Child Health J. 2008 Jul;12(4):469-77
references.pmid: 17690963
references.citation: Am J Epidemiol. 2004 Apr 1;159(7):702-6
references.pmid: 15033648
references.citation: Epidemiology. 2012 Jan;23(1):1-9
references.pmid: 22157298
references.citation: Health Serv Res. 2002 Oct;37(5):1387-401
references.pmid: 12479502
references.citation: Clin Perinatol. 2008 Jun;35(2):293-307, v
references.pmid: 18456070
references.citation: Obstet Gynecol. 2009 Jan;113(1):33-40
references.pmid: 19104357
references.citation: Hum Reprod. 2008 Mar;23(3):543-7
references.pmid: 18216039
references.citation: Br J Obstet Gynaecol. 1989 Nov;96(11):1297-303
references.pmid: 2611168
references.citation: Br J Obstet Gynaecol. 1999 Mar;106(3):227-32
references.pmid: 10426641