Damon Mayes

Impact of pregnancy-induced hypertension on fetal growth

OBJECTIVE The purpose of this study was to evaluate the effect of different types of pregnancy-induced hypertension on fetal growth. STUDY DESIGN A retrospective cohort study was conducted on the basis of 16,936 births from January 1, 1989, through December 31, 1990, by means of data from a population-based perinatal database in Suzhou, China. Pregnancy-induced hypertension was classified as gestational hypertension, preeclampsia, or severe preeclampsia-eclampsia. Univariate and multivariate regression analyses were performed to examine the effect of the various types of pregnancy-induced hypertension on gestational age, preterm birth, birth weight, low birth weight, and intrauterine growth restriction. RESULTS Gestation was 0.6 week shorter in women with severe preeclampsia than in normotensive women (P <.01). However, the risk of preterm birth was not increased with any classification of pregnancy-induced hypertension (for severe preeclampsia: adjusted odds ratio 1.75; 95% confidence interval, 0.88-3.47). After adjustment for duration of gestation and other confounders, preeclampsia and severe preeclampsia increased the risk of intrauterine growth restriction and low birth weight. The adjusted odds ratios of low birth weight were 2.65 (1.73-4.39) for preeclampsia and 2.53 (1.19-4.93) for severe preeclampsia. However, the risk of low birth weight was not increased significantly for gestational hypertension (adjusted odds ratio 1.56 [1.00-2.41]). CONCLUSION Preeclampsia increases the risk of intrauterine growth restriction and low birth weight.

Crohn's disease, pregnancy, and birth weight

OBJECTIVE:Although there is general agreement that conception should be avoided when Crohns disease is active, many questions remain unanswered for the woman with Crohns disease in remission who becomes pregnant.METHODS:Sixty-five charts of women with Crohns disease quiescent at the start of pregnancy were identified between January 1993 and December 1997. Each pregnancy was matched to a healthy control pregnancy by date, age, parity, smoking status, and gestational age ± 1 wk, and comparisons were carried out using matched analyses.RESULTS:The two groups were similar in terms of maternal height, weight, and body mass index (BMI), in addition to the matched variables. The incidence of pregnancy complications was similar for most of the complications examined, whereas the incidence of poor maternal weight gain differed significantly between the groups (17/65 vs 2/65, p < 0.001). Flare-up of the Crohns disease was seen in 13/65 (20%) of pregnancies. The greatest differences in neonatal outcomes were in terms of birth weight (3150 ± 80 g vs 3500 ± 60 g) and birth weight percentile (36.7%± 3.6% vs 57.5%± 3.4%). Overall, there were 16 (24.6%) small for gestational age (SGA) births in the Crohns group, compared with only one (1.5%) in the control group (p = 0.0007). Multivariate analysis was performed to identify factors predictive of SGA births in the Crohns group. Ileal Crohns disease was a statistically significant predictor (p = 0.035), whereas previous bowel resection trended toward statistical significance (p = 0.065).CONCLUSIONS:In view of the risk of low birth weight, all women with Crohns disease who become pregnant should be followed carefully during the pregnancy, particularly those who have ileal disease or who have previously undergone bowel resection. Furthermore, smoking cessation needs to be aggressively pursued in these patients.

Is maternal obesity a predictor of shoulder dystocia

OBJECTIVE: To explore the relationship between maternal obesity and shoulder dystocia while controlling for the potential confounding effects of other variables associated with obesity. METHODS: We performed a case‐control study of provincial delivery records audited by the Northern and Central Alberta Perinatal Outreach Program. Risk factors evaluated were selected based on previously published studies. Cases and controls were drawn from 45,877 live singleton cephalic vaginal deliveries weighing more than 2500 g between January 1995 and December 1997. There were 413 cases of shoulder dystocia (0.9% incidence). Controls (n = 845) were randomly chosen from the remainder of the target population to create a 1:2 case/control ratio. Univariate analysis with calculation of odds ratios (ORs) was used to determine which of the chosen risk factors were significantly related to the incidence of shoulder dystocia. Multivariable regression analyses were then used to determine the independently associated variables, and the adjusted ORs were obtained for each relevant risk factor. RESULTS: Maternal obesity was not significant as an independent risk factor for shoulder dystocia after adjusting for confounding variables (adjusted OR 0.9; 95% confidence interval [CI] 0.5, 1.6). Fetal macrosomia was the single most powerful predictor. The adjusted ORs were 39.5 (95% CI 19.1, 81.4) for birth weight greater than 4500 g and 9.0 (95% CI 6.5, 12.6) for birth weight between 4000 and 4499 g. CONCLUSION: The strongest predictors of shoulder dystocia are related to fetal macrosomia. For obese nondiabetic women carrying fetuses whose weights are estimated to be within normal limits, there is no increased risk of shoulder dystocia. (Obstet Gynecol 2003;101:24‐7.

Maternal Cell Contamination of Amniotic Fluid Samples Obtained by Open Needle Versus Trocar Technique of Amniocentesis

OBJECTIVE To determine the incidence of maternal cell contamination (MCC) in the open-needle amniocentesis sampling technique compared with the trocar-in-place technique. METHODS A retrospective analysis was conducted on 2,498 mid-trimester amniocenteses performed in two tertiary care centres in Canada. The University of Alberta centre used the open-needle (without the trocar) technique and the University of British Columbia centre used the standard (with the trocar in place) technique. Data were gathered regarding the nature of the amniotic fluid, number of needle passes, amniocentesis results, and the occurrence of maternal cell contamination. The statistical analysis used logistic regression, and controlled for the potential confounders of bloody fluid taps and requirement for more than one needle insertion. RESULTS The incidence of maternal cell contamination was 1.16% with the open-needle technique and 0.78% with the standard trocar-in-place technique (p < 0.315), with a power of 42%. CONCLUSION The data suggested there is no significant increase in maternal cell contamination with the open-needle versus trocar-in-place techniques of amniocentesis. However, the small sample size, combined with the low prevalence of the outcome of interest (MCC), provides insufficient power to draw firm conclusions about the difference in MCC between the two techniques.

Twin-to-twin transfusion syndrome: a review of 27 cases and the relationship between gestational age at diagnosis and serial amniocentesis on outcome

Abstract Objective: To review outcomes of twin-to-twin syndrome (TTTS) cases and to examine the relationship between gestational age at diagnosis and serial amniocentesis drainage on these outcomes. Methods: Charts were reviewed from a 5-year period. Charts with a diagnosis of TTTS and multiples with discordant growth, polyhydramnios, oligohydramnios, or intrauterine growth restriction were reviewed. Diagnosis of TTTS was confirmed by ultrasound and pathological examination. Cases with placental insufficiency or chromosomal, cardiac, or urinary tract abnormalities were excluded. Outcomes were: survival rates, gestational age at delivery, and birth weight. Results were analyzed using the χ 2 and t tests. Results: Overall survival rate was 71%. Mean gestational age at delivery was 27.8 weeks, and mean birth weight was 1,141 g. If diagnosis was made before 24 weeks of gestation, the survival rate was 50%; if it was made after 24 weeks of gestation, survival was 100%. If drainage was required, survival rate was 56%. If no drainage was required, survival was 100%. Conclusions: TTTS still is associated with significant morbidity and mortality. Other treatments, such as laser ablation, need to be investigated, particularly for the patients who present in the second trimester. Studies of long-term morbidity also are needed.

The Value of Routine Episiotomy in Forceps Deliveries

Abstract Objective: to determine the risk of third and fourth degree tears if episiotomy precedes operative forceps deliveries. Methods: a retrospective analysis was performed, identifying 319 women who had a forceps delivery. Two hundred and seventy-two women met our inclusion criteria term, singleton, cephalic presentation, with mid, low or outlet forceps). Patients having forceps deliveries with an episiotomy were compared to those with forceps deliveries and no episiotomy. Maternal age, parity, use of an epidural, gestational age, and birth weight were examined for each group. The incidence of third and fourth degree tears and the odds ratio between the two groups were determined. Results: there were no differences in demographic or clinical variables between the two groups. Compared to the patients without episiotomy (n = 46), patients having forceps deliveries with an episiotomy (n = 226) had a significantly higher incidence of third and fourth degree tears (odds ratio 2.8; 95% confidence interval 1.5–5.6). Conclusion: the routine use of episiotomy is possibly associated with an increased incidence of sphincteric injuries in patients undergoing forceps deliveries. The routine use of episiotomy with forceps delivery should be re-evaluated.

Maternal cell contamination of amniotic fluid samples obtained by open-needle versus trocar technique of amniocentesis

Abstract Objective: Maternal cell contamination (MCC) is rare in cultured amniotic fluid samples, but it poses a serious potential source of prenatal misdiagnosis. Our goal was to determine whether the amniocentesis sampling technique influences the incidence of maternal cell contamination. Study design: A retrospective study was performed on 2,498 amniocentesis results in two tertiary care centers in Canada. The University of Alberta used the open-needle technique, and the University of British Columbia used a technique with the trocar in place. We reviewed midtrimester amniocenteses performed by perinatologists on singleton male fetuses. We excluded all transplacental insertions. Data were gathered regarding the nature of the amniotic fluid, number of needle passes, amniocentesis results, and the occurrence of maternal cell contamination. Results: The incidence of MCC was similar at the two study centers: 1.16% and 0.78% at the University of Alberta and the University of British Columbia, respectively. The odds ratio for MCC with the open versus the trocar-in-place technique with use of logistic regression was 1.48 (95% CI, 0.3–3.3) with a P value less than 0.315, which is not significant. Bloody fluid taps and the number of needle insertions were both controlled for in the statistical analysis. Conclusion: The data indicate that there is no significant increase in maternal cell contamination with the open-needle technique of amniocentesis. We believe that open-needle amniocentesis has advantages for the patient and the physician and that it is a safe and reliable technique for amniocentesis.

Is Transperineal Ultrasonography of Cervical Length in Pregnant Women as Accurate as Endovaginal Ultrasonography? A Prospective, Blinded Comparison of Level of Agreement of Two Techniques

Abstract Objectives : To assess the accuracy of transperineal compared to endovaginal sonographic measurement of cervix length, and to assess the feasibility of an obstetrical resident attaining competence in transperineal sonographic measurement of cervix length. Methods : After attaining appropriate concordance in measurement between the three participating investigators (one obstetrical resident and two experienced sonographers), a prospective, blinded study was performed. Paired endovaginal and transperineal cervix length measurements were performed on 123 consenting pregnant women. Results : Concordance between the three investigators was easily established, demonstrating competence in transperineal cervix length measurement by the obstetrical resident. Although there was 85 percent correlation between endovaginal and transperineal cervix length measurements, the predetermined acceptante difference between the two measurements (1-5 mm) was not obtained, demonstrating that transperineal cervical length measurements are not as accurate as endovaginal measurements. ln addition, 15 percent of transperineal assessments were of insufficient quality for interpretations. Conclusions : Transperineal measurements are more difficult to perform well, the quality of the measurements are more often unacceptable, and they may not be as accurate or reliable as endovaginal measurements. It is a realistic objective for obstetrical residents to become competent in sonographic cervix length measurement, suggesting that it could be feasible for residents to perform endovaginal cervix length measurements in a labour and delivery setting for the assessment of women with symptoms of threatened preterm labour.