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Objective To estimate whether a history of fetal growth restriction, abruptio placentae, preeclampsia, or live preterm birth is associated with excess risk of stillbirth in a subsequent pregnancy. We also estimated the maternal and paternal contributions to such effects. Methods This was a population-based cohort study from 1967 to 2005. Pairs of first and second, second and third, third and fourth, and fourth and fifth births were identified among all births from the Medical Birth Registry of Norway; 747,221 pairs with the same parents, 51,708 with the same mother and different father, and 65,602 with the same father and different mother. The associations of gestational age categories (22-27, 28-32, 33-36, and at or above 37 weeks), small for gestational age (SGA), preeclampsia, and abruptio placenta in the first pregnancy with stillbirth and late abortion in the second were assessed by odds ratios (ORs) obtained by logistic regression. Results The baseline rate of stillbirth during the study period was 1.0% of all births from 16 weeks of gestation. After births with gestational age 22-27, 28-32, and 33-36 weeks of gestation, stillbirth was six, three and two times more likely to occur than after a term birth (OR 5.7, 95% confidence interval [CI] 4.2-7.6; OR 2.6, 95% CI 2.1-3.3; and OR 1.7, 95% CI 1.5-1.9, respectively). Odds ratios of stillbirth subsequent to pregnancies with SGA, preeclampsia, and abruptio placentae were 1.7 (95% CI 1.6-1.9), 1.6 (95% CI 1.5-1.9), and 2.8 (95% CI 2.2-3.5), respectively, and increased with severity of the conditions. Gestational age below 33 weeks with preeclampsia or SGA carried 6-9 and 6-13-fold effects on later stillbirth, respectively. Men who fathered a pregnancy with preterm preeclampsia were significantly more likely to father a stillbirth in another woman (OR 2.4, 95% CI 1.1-5.5). Conclusion Live preterm birth, fetal growth restriction, preeclampsia, and abruptio placenta are strongly associated with later stillbirth. Level of evidence II.

OBJECTIVE To explore the association between mode of delivery and subsequent fertility. METHODS Deliveries registered in the Medical Birth Registry of Norway were linked to mothers through national identification numbers. The study population was 596,341 women who had their first delivery during 1967-1996, and who were followed up through 2003. We compared rates of continuation to a subsequent birth according to mode of previous delivery (cesarean compared with vaginal). RESULTS If the first child survived the first year of life, cesarean delivery was associated with a significantly reduced probability of a second birth (relative risk [RR] 0.82, 95% confidence interval [CI] 0.81-0.83 during 1967-1981, and RR 0.88, 95% CI 0.88-0.89 during 1982-1996). Following a stillbirth or an infant loss, the association was less strong during 1967-1981 (RR 0.93, 95% CI 0.89-0.97) and no longer significant during 1982-1996 (RR 1.00, 95% CI 0.97-1.03). A similar pattern was observed from the second to the third birth and in subgroup analyses of women with preeclampsia or breech presentation and in an obstetric low-risk group. CONCLUSION Cesarean delivery was more strongly associated with reduced fertility if the infant survived than if it was stillborn or died. This suggests that the reduced fertility was to a large degree voluntary and not related to the indication, nor to any physical consequence, of the cesarean delivery. LEVEL OF EVIDENCE II.

OBJECTIVE: Long-term intellectual performance in breechpresented infants may be negatively affected by vaginal delivery. We evaluated the effect of presentation at birth and delivery mode on intellectual performance at age 18 years in a nationwide population study. METHODS: We studied 8,738 male infants in breech and 384,832 males in cephalic presentation registered in the Medical Birth Registry of Norway, 1967‐1979, and linked to data registered at the National Conscript Service, 1984‐ 1999. Test scores of intelligence testing at conscription were presented as standard nine (“stanine”) scores. Mean staninescoresandoddsratiosoflowscorewerecomputedand adjusted for birth order, maternal age, and education. RESULTS: Mean stanine score was slightly higher among breech-presented males than among cephalic-presented males (5.26 versus 5.22, P .05), whereas after adjustment the difference disappeared (P .3). Breech-presented infants had lower mean scores if delivered by cesarean compared with vaginal breech delivery (P .03), and cephalicpresented males scored lower if their mothers had a cesarean delivery instead of a vaginal delivery (P < .001). Comparing cesarean and vaginal delivery in breech births, the odds ratio of having a stanine score less than or equal to 3 was 1.12 (95% confidence interval 0.92,1.36), after adjustment for confounding factors. CONCLUSION: Presentation at birth did not affect adult intellectual performance. Cesarean delivery of breech-presented infants did not improve adult intellectual performance when compared with a vaginal delivery. The excess perinatal hazards of breech-presented infants with a vaginal delivery were not reflected in adult intellectual performance. (Obstet Gynecol 2005;105:4‐11. © 2005 by The American College of Obstetricians and Gynecologists.) LEVEL OF EVIDENCE: II-2

The Recurrence Risk of Adverse Outcome in the Second Pregnancy in Women With Rheumatic Disease

Objective: To assess subsequent pregnancy rates and recurrence of breech, as well as interpregnancy interval after a breech presentation. Methods: We conducted a national population registry-based study using data from 1967 to 1994, with maternal record linkage of sibships, comprising the first to the fourth birth of a mother. Results: The subsequent pregnancy rate after a surviving breech birth was lower than after a surviving nonbreech birth. Women with two births, of which one was a perinatal loss, had a higher subsequent pregnancy rate, compared with those who had surviving infants. The subsequent pregnancy rate was lower after a cesarean delivery irrespective of presentation. The interpregnancy interval was shorter if the previous infant died, whereas presentation did not influence the interval. The adjusted odds ratio of recurrence of breech increased from 4.32 (95% confidence interval [CI] 4.08, 4.59) after one previous breech delivery to 28.1 (95% CI 12.2, 64.8) after three. Conclusion: Breech and cesarean delivery lowered the subsequent pregnancy rate, probably because of the women’s decision not to reproduce. Thus, preconceptional counseling with information, support, and reassurance regarding future pregnancies and deliveries might reduce the discouraging effect. A high odds ratio of recurrence of breech suggests effects of recurring specific causal factors of either genetic or more permanent environmental origin.

Objective To identify factors associated with post-term birth and factors associated with adverse outcomes in post-term births. Methods The sample was a 10-year cohort (1978–1987) of term ( n = 379,445) and post-term ( n = 65,796) births from the Medical Birth Registry of Norway. Gestational age was based on mothers' recall of the last menstrual period. Multivariate analyses included proportional hazards regression and binomial logistic regression. Results After controlling for covariates, there was only a slightly increased risk of perinatal mortality in post-term as compared with term births (adjusted relative risk [RR] 1.11; 95% confidence interval [CI] 0.97,1.27). For post-term births, risk factors for perinatal mortality were small size for gestational age (SGA) (adjusted RR 5.68; 95% CI 4.37, 7.38) and maternal age 35 years or older (adjusted RR 1.88; 95% CI 1.22, 2.89), whereas large size for gestational age (LGA) was a protective factor (adjusted RR 0.51; 95% CI 0.26, 1.00). Similar risk factor RRs were found for perinatal mortality in term births. Fetal distress was associated with both SGA and post-term birth; labor dysfunction and obstetric trauma were associated with both LGA and post-term birth; shoulder dystoda and maternal hemorrhage were associated with LGA only. Conclusions Among post-term births, maternal complications were generally associated with larger fetal size, and fetal complications were associated with smaller fetal size. The evidence for an adverse impact on perinatal mortality of post-term birth is weak once other factors are taken into account.