Pregestational maternal risk factors for preterm and term preeclampsia: A population-based cohort study.

INTRODUCTION: Most studies on factors affecting the risk of preeclampsia have not separated preterm from term preeclampsia, and we still know little about whether the predisposing conditions have a differentiated effect on the risk of preterm and term preeclampsia. Our aim was to assess whether diabetes type 1 and 2, chronic kidney disease, asthma, epilepsy, rheumatoid arthritis and chronic hypertension were differentially associated with preterm and term preeclampsia. MATERIAL AND METHODS: This is a nationwide, population-based cohort study containing all births registered in the Medical Birth Registry of Norway from 1999 to 2016. Multinomial logistic regression analysis was used to estimate relative risk ratios (RRRs) with 95% confidence intervals (95% CIs), adjusting for maternal age, parity, multiple gestation and all other studied maternal risk factors. RESULTS: We registered 1 044 860 deliveries, of which 9533 (0.9%) women had preterm preeclampsia (<37 weeks) and 26 504 (2.5%) women had term preeclampsia (>37 weeks). Most of the assessed maternal risk factors were associated with increased risk for both preterm and term preeclampsia, with adjusted RRRs ranging from 1.2 to 10.5 (preterm vs no preeclampsia) and 0.9-5.7 (term vs no preeclampsia). Diabetes type 1 and 2 (RRR preterm vs term preeclampsia 2.89, 95% CI 2.46-3.39 and RRR 1.68, 95% CI 1.25-2.25, respectively), chronic kidney disease (RRR 1.55, 95% CI 1.11-2.17) and chronic hypertension (RRR 1.85, 95% CI 1.63-2.10) were more strongly associated with preterm than term preeclampsia in adjusted analyses. For asthma, epilepsy and rheumatoid arthritis, RRRs were closer to one and not significant when comparing risk of preterm and term preeclampsia. Main results were similar when using a diagnosis at <34 weeks to define preterm preeclampsia. CONCLUSIONS: Diabetes type 1 and 2, chronic kidney disease and chronic hypertension were more strongly associated with preterm than term preeclampsia.

Use of antihistamines before or during pregnancy and risk of early-onset pre-eclampsia in allergic women: a population-based cohort study.

OBJECTIVE: We have previously found that allergy is a risk factor for early-onset pre-eclampsia. The aim of this study was to assess the association between pregestational maternal use of antihistamines and early-onset pre-eclampsia. DESIGN: A population-based cohort study. SETTING AND PARTICIPANTS: All women giving birth in Norway 2004-2016, including 692 487 pregnancies. Data from the Medical Birth Registry of Norway were linked with data from the Norwegian Prescription Database. Prescriptions of antihistamines were divided into three groups: before pregnancy (<6 months), early pregnancy (<20 weeks) and late pregnancy (20-36 weeks). ORs with 95% CIs for pre-eclampsia <34 and <37 weeks by antihistamine use were estimated by logistic regression and stratified on multiple pregnancy and parity. Predicted proportions (%) with 95% CIs were estimated. INTERVENTIONS: Use of antihistamines in relation to pregnancy in allergic women. MAIN OUTCOME MEASURES: Development of early-onset pre-eclampsia. RESULTS: 2997 (0.43%) and 5769 (0.83%) women had pre-eclampsia <34 and <37 weeks, respectively. Use of antihistamines before and in early pregnancy was associated with a risk of developing early-onset pre-eclampsia that was comparable to the background population (OR 1.0, 95% CI 0.8 to 1.2 and OR 0.9, 95% CI 0.7 to 1.1, respectively). Antihistamine use only in late pregnancy was not treated as exposure, but as an indicator of allergy, and was associated with an increased risk of early-onset pre-eclampsia (OR 1.8, 95% CI 1.5 to 2.2). Predicted proportions of pre-eclampsia <34 weeks were significantly lower in women using antihistamines before (0.41%, 95% CI 0.34 to 0.49) and in early pregnancy (0.37%, 95% CI 0.31 to 0.44), compared with women using antihistamines after placentation (0.69%, 95% CI 0.57 to 0.83). Results were similar for pre-eclampsia <37 weeks. CONCLUSIONS: Antihistamine use before or during placentation was associated with reduced risk of developing early-onset pre-eclampsia in allergic women compared with women using antihistamines after placentation.

Fetal molding examined with transperineal ultrasound and associations with position and delivery mode.

BACKGROUND: To accommodate passage through the birth canal, the fetal skull is compressed and reshaped, a phenomenon known as molding. The fetal skull bones are separated by membranous sutures that facilitate compression and overlap, resulting in a reduced diameter. This increases the probability of a successful vaginal delivery. Fetal position, presentation, station, and attitude can be examined with ultrasound, but fetal head molding has not been previously studied with ultrasound. OBJECTIVE: This study aimed to describe ultrasound-assessed fetal head molding in a population of nulliparous women with slow progress in the second stage of labor and to study associations with fetal position and delivery mode. STUDY DESIGN: This was a secondary analysis of a population comprising 150 nulliparous women with a single fetus in cephalic presentation, with slow progress in the active second stage with pushing. Women were eligible for the study when an operative intervention was considered by the clinician. Molding was examined in stored transperineal two-dimensional and three-dimensional acquisitions and differentiated into occipitoparietal molding along the lambdoidal sutures, frontoparietal molding along the coronal sutures, and parietoparietal molding at the sagittal suture (molding in the midline). Molding could not be classified if positions were unknown, and these cases were excluded. We measured the distance from the molding to the head midline, molding step, and overlap of skull bones and looked for associations with fetal position and delivery mode. The responsible clinicians were blinded to the ultrasound findings. RESULTS: Six cases with unknown position were excluded, leaving 144 women in the study population. Fetal position was anterior in 117 cases, transverse in 12 cases, and posterior in 15 cases. Molding was observed in 79 of 144 (55%) fetuses. Molding was seen significantly more often in occiput anterior positions than in non-occiput anterior positions (69 of 117 [59%] vs 10 of 27 [37%]; P=.04). In occiput anterior positions, the molding was seen as occipitoparietal molding in 68 of 69 cases and as parietoparietal molding in 1 case with deflexed attitude. Molding was seen in 19 of 38 (50%) of occiput anterior positions ending with spontaneous delivery, 42 of 71(59%) ending with vacuum extraction, and in 7 of 8 (88%) with failed vacuum extraction (P=.13). In 4 fetuses with occiput posterior positions, parietoparietal molding was diagnosed, and successful vacuum extraction occurred in 3 cases and failed extraction in 1. Frontoparietal molding was seen in 2 transverse positions and 4 posterior positions. One delivered spontaneously; vacuum extraction failed in 3 cases and was successful in 2. Only 1 of 11 fetuses with either parietoparietal or frontoparietal molding was delivered spontaneously. CONCLUSION: The different types of molding can be classified with ultrasound. Occipitoparietal molding was commonly seen in occiput anterior positions and not significantly associated with delivery mode. Frontoparietal and parietoparietal moldings were less frequent than reported in old studies and should be studied in larger populations with mixed ethnicities.

Maternal allergy as an isolated risk factor for early-onset preeclampsia: An epidemiological study.

Immunological mechanisms underlying the development of preeclampsia are well known, but no association to allergy has yet been demonstrated. The aim of this study was to assess the correlation between maternal pre-gestational allergy, and early-onset and late-onset preeclampsia, respectively. It was a retrospective cohort study including all women giving birth in the Norwegian cities of Stavanger (1996-2014) and Bergen (2009-2014). Pre-gestational asthma, allergy, other known risk factors for preeclampsia, maternal age and parity were obtained from the electronic medical record system. The main outcome variables were early-onset and late-onset preeclampsia (before and after 34 completed weeks of gestation, respectively). We used multinomial logistic regression to estimate odds ratios (OR) with 95% confidence intervals (95% CI) for early and late-onset preeclampsia in women with pre-gestational allergy when compared to women without allergy, adjusting for covariates. Predicted probabilities for the outcomes were also calculated. Of the 110 064 included pregnancies, 2 799 developed late-onset preeclampsia (2.5%) and 348 developed early-onset preeclampsia (0.3%). Pre-gestational allergy increased the risk of early-onset preeclampsia (OR 1.7, 95% CI 1.3-2.4), and reduced the risk of late-onset preeclampsia (OR 0.8, 95% CI 0.7-0.9). These findings add valuable information on preeclampsia as an immunological complication of pregnancy and corroborate the understanding of early- and late-onset preeclampsia as two different entities.