Susanne Albrechtsen

Pregnancy outcome in women before and after cervical conisation : population based cohort study

Objectives To examine the consequences of cervical conisation in terms of adverse outcome in subsequent pregnancies. Design Population based cohort study. Data sources Data on cervical conisation derived from the Cancer Registry of Norway and on pregnancy outcome from the Medical Birth Registry of Norway, 1967-2003. 15 108 births occurred in women who had previously undergone cervical conisation and 57 136 who subsequently underwent cervical conisation. In the same period there were 2 164 006 births to women who had not undergone relevant treatment (control). Results The proportion of preterm delivery was 17.2% in women who gave birth after cervical conisation versus 6.7% in women who gave birth before cervical conisation and 6.2% in women who had not undergone cervical conisation. The relative risk of a late abortion (<24 weeks’ gestation) was 4.0 (95% confidence interval 3.3 to 4.8) in women who gave birth after cervical conisation compared with no cervical conisation. The relative risk of delivery was 4.4 (3.8 to 5.0) at 24-27 weeks, 3.4 (3.1 to 3.7) at 28-32 weeks, and 2.5 (2.4 to 2.6) at 33-36 weeks. The relative risk of preterm delivery declined during the study period and especially of delivery before 28 weeks’ gestation. Conclusion Cervical conisation influences outcome in subsequent pregnancies in terms of an increased risk of preterm delivery, especially in the early gestational age groups in which the clinical significance is highest. A careful clinical approach should be taken in the selection of women for cervical conisation and in the clinical care of pregnancies after a cervical conisation.

Peripartum hysterectomy‐incidence and maternal morbidity

Background. The aim of the study was to find the incidence and clinical implications of peripartum hysterectomy in our department and to identify women at risk to improve treatment before resorting to hysterectomy.

Evaluation of a protocol for selecting fetuses in breech presentation for vaginal delivery or cesarean section.

OBJECTIVE Our purpose was to evaluate, with respect to obstetric intervention and neonatal outcome, a protocol for selecting fetuses in breech presentation for vaginal delivery or cesarean section. STUDY DESIGN A clinical follow-up study was performed between 1984 and 1992 of all term singleton deliveries in breech presentation. Each case selected for vaginal delivery had a matched control in vertex presentation. RESULTS A total of 1212 infants presented as breech. Vaginal delivery increased from 45% to 57% (p = 0.004), and cesarean section for failure of vaginal delivery declined from 21% to 6% (p < 0.00001). None, however, died or had long-term sequelae because of a complicated or failed vaginal breech delivery. A total of 8.8% of those delivered vaginally in breech versus 5.0% of those in vertex presentation were admitted to the neonatal intensive care unit (p = 0.009). Among those with vaginal delivery, 2.5% in breech presentation were given the clinical diagnosis of birth asphyxia versus none in the vertex position (p = 0.0001). CONCLUSION Breech presentation at term may be selected for vaginal delivery if properly managed.

Prevalence, Risk Factors and Outcomes of Velamentous and Marginal Cord Insertions: A Population-Based Study of 634,741 Pregnancies

Objectives To determine the prevalence of, and risk factors for anomalous insertions of the umbilical cord, and the risk for adverse outcomes of these pregnancies. Design Population-based registry study. Setting Medical Birth Registry of Norway 1999–2009. Population All births (gestational age >16 weeks to <45 weeks) in Norway (623,478 singletons and 11,263 pairs of twins). Methods Descriptive statistics and odds ratios (ORs) for risk factors and adverse outcomes based on logistic regressions adjusted for confounders. Main outcome measures Velamentous or marginal cord insertion. Abruption of the placenta, placenta praevia, pre-eclampsia, preterm birth, operative delivery, low Apgar score, transferral to neonatal intensive care unit (NICU), malformations, birthweight, and perinatal death. Results The prevalence of abnormal cord insertion was 7.8% (1.5% velamentous, 6.3% marginal) in singleton pregnancies and 16.9% (6% velamentous, 10.9% marginal) in twins. The two conditions shared risk factors; twin gestation and pregnancies conceived with the aid of assisted reproductive technology were the most important, while bleeding in pregnancy, advanced maternal age, maternal chronic disease, female foetus and previous pregnancy with anomalous cord insertion were other risk factors. Velamentous and marginal insertion was associated with an increased risk of adverse outcomes such as placenta praevia (OR = 3.7, (95% CI = 3.1–4.6)), and placental abruption (OR = 2.6, (95% CI = 2.1–3.2)). The risk of pre-eclampsia, preterm birth and delivery by acute caesarean was doubled, as was the risk of low Apgar score, transferral to NICU, low birthweight and malformations. For velamentous insertion the risk of perinatal death at term was tripled, OR = 3.3 (95% CI = 2.5–4.3). Conclusion The prevalence of velamentous and marginal insertions of the umbilical cord was 7.8% in singletons and 16.9% in twin gestations, with marginal insertion being more common than velamentous. The conditions were associated with common risk factors and an increased risk of adverse perinatal outcomes; these risks were greater for velamentous than for marginal insertion.

Predicting preeclampsia in the second pregnancy from low birth weight in the first pregnancy.

Objective To evaluate the effect of low birth weight adjusted for gestational age in first pregnancies on preeclampsia in second pregnancies and to estimate the proportion of preeclampsia in second pregnancies attributable to histories of LBW for gestational age. Methods We conducted a cohort study based on linked data from the Medical Birth Registry of Norway, which covered all births in 1967–1992. Results Women who delivered infants under the third percentile birth weight were three times more likely to have initial or recurrent preeclampsia in second pregnancies than those who delivered infants at or above the tenth percentile. After adjusting for maternal age, year of birth, interpregnancy interval, education, chronic hypertension, diabetes mellitus, and change of partner, the increased risk persisted. Birth weight below the tenth percentile in the first delivery accounted for 10% of the total cases of preeclampsia in the second pregnancy and 30% of recurrent cases. Conclusion A history of low birth weight adjusted for gestational age is associated significantly with subsequent occurrence as well as recurrence of preeclampsia. These findings are consistent with the hypothesis of a shared etiologic factor or recurrent pathophysiologic mechanism for preeclampsia and fetal growth restriction. A history of fetal smallness for gestational age is found in a substantial proportion of all cases of preeclampsia and thus seems to be important in the etiology of preeclampsia.

Obstetric history and the risk of placenta previa

Objective. To evaluate secular trends in the occurrence of placenta previa and whether placenta previa is associated with the outcome of previous pregnancies, cesarean section, and sociodemographic factors.

Manual removal of the placenta, Incidence and clinical significance

OBJECTIVE To determine the incidence and complications related to manual removal of the placenta. METHODS Review of hospital medical records from 1990 throughout 1994. One thousand five hundred and two vaginal deliveries from 1984 1992 were used for comparisons. RESULTS A total of 24,750 deliveries were registered during the five year study period. Placenta was removed manually in 165 women (0.6%). The use of general anesthesia for manual removal of placenta decreased from 74% in 1990 to 19% in 1994. Spinal analgesia was applied from 1993, and it was used in 42% of the women in 1994. Of 74 parous women, 12 (16%) had experienced retained placenta before. The average difference in the hemoglobin concentration between the prenatal and the postoperative values was 3.4 g/dl among the patients, and 10% required blood transfusion (1-4 units). Among the controls, there was no decrease in the average hemoglobin concentration, and only 0.5 needed blood transfusion. Endometritis following manual removal was detected in 1.8% of the patients and 1.5% among the controls. Despite manual removal, five women (3%) were considered to have retained placental fragments two days or later after delivery, which required curettage. CONCLUSIONS Placenta needed to be removed manually in 0.60% of all deliveries in our department. It was associated with increased incidence of hemorrhage and consequently low hemoglobin values. Women with a history of retained placenta have an increased risk of recurrence of retained placenta in subsequent deliveries.

Reproductive career after breech presentation: subsequent pregnancy rates, interpregnancy interval, and recurrence

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 womens 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.

Breech birth at term: vaginal delivery or elective cesarean section? A systematic review of the literature by a Norwegian review team

Whether planned cesarean section is better than planned vaginal delivery for breech presentation at term (37–42 weeks) has been the subject of debate for some time. Apart from two small randomized controlled trials (1,2) from the early 1980s, the evidence on breech delivery was based on patient series and register studies, which have been considered to be of low scientific value. However, in October 2000 the randomized multicenter Term Breech Trial (TBT) was published in The Lancet (3), with a 3-month follow-up in 2002 (4). The study included 2083 deliveries from 121 obstetric departments in 26 countries. One Danish and one Finnish, but no Norwegian, obstetric departments took part in the study. The TBT concluded that planned cesarean section led to a significantly better perinatal outcome than planned vaginal delivery. The occurrence of maternal complications was similar for the two groups. Not surprisingly, the TBT ignited intense discussion among doctors, midwives and the public. Data from the Medical Birth Registry of Norway show a slight increase in the incidence of breech presentation among infants with a birthweight greater than 2499 g in the period 1981–98, and the incidence is 2.9% in 1998 (Fig. 1). In Norway, 40% of approximately 1500 annual term breech infants are currently delivered vaginally (Fig. 2). A change to routine use of cesarean section would have an unprecedented impact on clinical practice in Norway. The use of external cephalic version on the Norwegian population has not been studied previously. A review team was therefore assigned to review (5,25) all current literature on term breech deliveries as well as on external cephalic version, using predetermined standard literature review methodology.

Risk factors for unexplained antepartum fetal death in Norway 1967-1998

OBJECTIVE To relate unexplained antepartum fetal death with maternal and fetal characteristics in order to identify risk factors. DESIGN Population-based study based on records of 1,676,160 singleton births with gestational age > or =28 weeks. Unexplained antepartum fetal death was defined as fetal death before labour without known fetal, placental, or maternal pathology. RESULTS Although unexplained fetal mortality in general declined from 2.4 per 1000 births in 1967-1976 to 1.6 in 1977-1998, the proportion among all fetal deaths increased from 30% to 43% during the same period of observation. Unexplained fetal death occurred later in gestation than explained. From 39 weeks of gestation, the risk increased progressively to 50/10,000 in women aged > or =35 years and <10/10,000 in women <25 years. In birth order > or =5, the risk was particularly high after 39 weeks of gestation. For birth weight percentile 2.5-9.9 and > or =97.5, unexplained fetal death was four and three times more likely to occur, respectively. We found an additive effect of maternal age and birth weight percentile 2.5-9.9. Women with less than 10 years education had higher risk than women with 13 years or more (OR=1.6). Weaker associations were observed with female gender, unmarried mothers, and winter season. CONCLUSIONS Unexplained antepartum fetal death occurred later in gestation than explained and was associated with high maternal age, multiparity, low education, and moderately low and high birth weight percentile. The increased risk in post-term pregnancies and the additive effect of maternal age and birth weight percentile 2.5-9.9 suggests that older women would benefit from monitoring of fetal growth.