Hannah Missfelder-Lobos

The Effect of Delaying Childbirth on Primary Cesarean Section Rates

Background The relationship between population trends in delaying childbirth and rising rates of primary cesarean delivery is unclear. The aims of the present study were (1) to characterize the association between maternal age and the outcome of labor, (2) to determine the proportion of the increase in primary cesarean rates that could be attributed to changes in maternal age distribution, and (3) to determine whether the contractility of uterine smooth muscle (myometrium) varied with maternal age. Methods and Findings We utilized nationally collected data from Scotland, from 1980 to 2005, and modeled the risk of emergency cesarean section among women delivering a liveborn infant in a cephalic presentation at term. We also studied isolated myometrial strips obtained from 62 women attending for planned cesarean delivery in Cambridge, England, from 2005 to 2007. Among 583,843 eligible nulliparous women, there was a linear increase in the log odds of cesarean delivery with advancing maternal age from 16 y upwards, and this increase was unaffected by adjustment for a range of maternal characteristics (adjusted odds ratio for a 5-y increase 1.49, 95% confidence interval [CI] 1.48–1.51). Increasing maternal age was also associated with a longer duration of labor (0.49 h longer for a 5-y increase in age, 95% CI 0.46–0.51) and an increased risk of operative vaginal birth (adjusted odds ratio for a 5-y increase 1.49, 95% CI 1.48–1.50). Over the period from 1980 to 2005, the cesarean delivery rate among nulliparous women more than doubled and the proportion of women aged 30–34 y increased 3-fold, the proportion aged 35–39 y increased 7-fold, and the proportion aged ≥40 y increased 10-fold. Modeling indicated that if the age distribution had stayed the same over the period of study, 38% of the additional cesarean deliveries would have been avoided. Similar associations were observed in multiparous women. When studied in vitro, increasing maternal age was associated with reduced spontaneous activity and increased likelihood of multiphasic spontaneous myometrial contractions. Conclusions Delaying childbirth has significantly contributed to rising rates of intrapartum primary cesarean delivery. The association between increasing maternal age and the risk of intrapartum cesarean delivery is likely to have a biological basis.

Individualized risk assessment for adverse pregnancy outcome by uterine artery Doppler at 23 weeks.

OBJECTIVE To provide individualized risk prediction of severe adverse pregnancy outcome based on uterine artery Doppler screening at 23 weeks. METHODS Color Doppler assessment of the uterine arteries was carried out in 5121 women attending for routine care at 23 weeks in two inner‐city obstetric units. The mean uterine artery pulsatility index (PI) was calculated, and the likelihood ratios in relation to PI were generated for severe adverse outcome. This was defined as fetal death, placental abruption, and delivery before 34 weeks associated with preeclampsia and birth weight less than the 10th centile. RESULTS The likelihood of severe adverse pregnancy outcome increased quadratically with mean uterine artery PI. This relationship was not affected by maternal age, ethnicity, or parity. At a mean PI of 1.45, the 95th centile for our population, the likelihood ratio for severe adverse pregnancy outcome was 5. Cigarette smoking had an additional contribution to PI in predicting severe adverse outcome, roughly doubling the risk for a given PI. CONCLUSION The individualized risk of severe adverse pregnancy outcome can be determined by uterine artery Doppler screening at 23 weeks and knowledge of cigarette smoking history. Such individualized risk would allow ultrasound resources and clinical follow‐up to be tailored to the pregnant woman for the most appropriate use of antenatal care.

Comparison of color Doppler uterine artery indices in a population at high risk for adverse outcome at 24 weeks' gestation

To compare uterine artery Doppler velocity and impedance indices in the presence and absence of uterine artery waveform notches, in the prediction of adverse pregnancy outcome in high‐risk women.

The NTplus method of screening for Down syndrome: achieving the 2010 targets?

The performance of pregnancy‐associated plasma protein‐A (PAPP‐A) as a first trimester trisomy 21 marker is hypothesized to improve below 11 weeks, whereas β‐human chorionic gonadotrophin (hCG) is better after 14 weeks. We audited a model combining early PAPP‐A (9–10 weeks) with NT (11–13 weeks and 6 days) and early triple test (>14 weeks).

Stimulation of Contractions in Human Myometrium by Serotonin is Unmasked by Smooth Muscle Relaxants

Objective. The aim of this study was to investigate the ability of serotonin to increase contractions in human myometrium. Methods. Isometric tension measurements were used to determine the effect of increasing doses of serotonin on strips of human myometrium obtained at the time of cesarean section. Results. Serotonin had little or no effect on the spontaneous activity of myometrium strips in control conditions. In tissue where this activity had been reduced by either forskolin or diazoxide, serotonin caused a dose-dependent increase in contractions and produced up to a 3-fold increase in contractions over basal activity. Conclusions.The ability of serotonin to increase contractions in the uterus appears to depend on the background activity of the tissue and is greatest in quiescent tissue. It is therefore possible that in quiescent, preterm myometrium, aberrant serotonin signaling could contribute to preterm labor. Serotonin may also play a key role in the postpartum prevention of uterine atony and consequent hemorrhage.

Umbilical artery pulsatility index and fetal abdominal circumference in isolated gastroschisis

To investigate changes in abdominal circumference (AC) and umbilical artery pulsatility index (UA‐PI) with gestation in fetuses with isolated gastroschisis, and to determine whether a relationship exists between UA‐PI and fetal AC.

OP29.06: Umbilical artery PI and fetal abdominal circumference in gastroschisis

Digital analysis of the placenta was performed using ‘Image J’ software (http://rsb.info.nih.gov/ij). Placentas were weighed, and measurements were taken of the placental axes and, those intersecting the cord insertion. We derived: eccentricity index (range 0–1) describing the shape of the placenta; cord centrality index (CCI) (range 0–1) describing the distance of umbilical cord insertion from the centre of placenta and coiling index describing the number of coils per cm length of umbilical cord. Results: See Table 1. Conclusions: Studies have shown the smaller placentas for smaller babies and other morphological abnormalities of placenta in IUGR cases. Low birth weight has also been associated with hypercoiling of the cord and peripheral insertion of the umbilical cord. This study did not show any difference in placental indices for babies with birth weight percentile ≤ 10th compared to a reference population.

P20.02: The relationship between abdominal circumference and middle cerebral artery Doppler z-scores in severe early onset fetal growth restriction: Poster abstracts

A. J. Talmor1, A. Daemen4, E. Murdoch5, H. Missfelder-Lobos1, B. De Moor3, D. Timmerman2, T. Bourne4,2, C. Lees1 1Department of Fetal Medicine, Obstetrics and Gynaecology, Addenbrooke’s Hospital, Cambridge University Hospitals NHS Trust, Cambridge, United Kingdom; 2Department of Obstetrics and Gynaecology, University Hospitals KU Leuven, Leuven, Belgium; 3Department of Electrical Engineering (ESAT), Katholieke Universiteit, Leuven, Belgium; 4Imperial College London, Imperial College London, Hammersmith Campus, Du Cane Road, London, United Kingdom; 5Department of Neonatology, Addenbrooke’s Hospital, Cambridge University Hospitals NHS Trust, Cambridge, United Kingdom