Xi-Kuan Chen

Association of caesarean delivery for first birth with placenta praevia and placental abruption in second pregnancy

Objective  To quantify the risk of placenta praevia and placental abruption in singleton, second pregnancies after a caesarean delivery of the first pregnancy.

Paternal age and adverse birth outcomes: teenager or 40+, who is at risk?

BACKGROUND Most previous studies on the effect of paternal age have focused on the association of advanced paternal age with congenital anomalies. The objective of this study was to determine whether paternal age is associated with the risk of adverse birth outcomes, independent of maternal confounders. METHODS We carried out a retrospective cohort study of 2 614 966 live singletons born to married, nulliparous women aged 20-29 years between 1995 and 2000 in the USA. Multiple logistic regressions were applied to estimate the independent effect of paternal age on adverse birth outcomes. RESULTS Compared with infants born to fathers aged 20-29 years, infants fathered by teenagers (<20 years old) had an increased risk of preterm birth [odds ratio (OR) = 1.15, 95% confidence interval (CI): 1.10, 1.20], low birth weight (OR = 1.13, 95% CI: 1.08, 1.19), small-for-gestational-age births (OR = 1.17, 95% CI: 1.13, 1.22), low Apgar score (OR = 1.13, 95% CI: 1.01, 1.27), neonatal mortality (OR = 1.22, 95% CI: 1.01, 1.49) and post-neonatal mortality (OR = 1.41, 95% CI: 1.09, 1.82). Advanced paternal age (> or =40 years) was not associated with the risk of adverse birth outcomes. CONCLUSIONS Teenage fathers carry an increased risk of adverse birth outcomes that is independent of maternal confounders, whereas advanced paternal age is not an independent risk factor for adverse birth outcomes.

Adequacy of prenatal care and neonatal mortality in infants born to mothers with and without antenatal high-risk conditions

Background:  Previous studies have found that inadequate prenatal care was associated with increased neonatal mortality in the general pregnant women.

Increased risks of neonatal and postneonatal mortality associated with teenage pregnancy had different explanations

OBJECTIVE To determine the potential pathway of the association between teenage pregnancy and neonatal and postneonatal mortality. STUDY DESIGN AND SETTING We carried out a retrospective cohort study of 4,037,009 nulliparous pregnant women under 25 years old who had a live singleton birth during 1995 to 2000, based on linked birth and infant death data set of the United States. RESULTS Teenage pregnancy (10-19 years old) was associated with increased neonatal mortality (odds ratio [OR]: 1.20, 95% confidence interval [CI]=1.16-1.24) and postneonatal mortality (OR: 1.47, 95% CI=1.41-1.54) after adjustment for potential confounders. With further adjustment for weight gain during pregnancy, teenage pregnancy was still associated with increased risk of neonatal (OR: 1.23, 95% CI=1.19-1.28) and postneonatal mortality (OR: 1.48, 95% CI=1.42-1.55). When adjustment was made for gestational age at birth, there was no association of teenage pregnancy with neonatal mortality (OR: 0.98, 95% CI=0.95-1.02), whereas there was significant association with postneonatal mortality (OR: 1.40, 95% CI=1.34-1.46). CONCLUSION The increased risk of neonatal death associated with teenage pregnancy is largely attributable to higher risk of preterm births, whereas increased postneonatal mortality is independent of the known confounders and gestational age at birth.

General obstetrics: Pregnancy‐induced hypertension is associated with lower infant mortality in preterm singletons

Objective  To assess the association between pregnancy‐induced hypertension (PIH) and infant mortality.

In Vitro Fertilization is Associated with an Increased Risk for Preeclampsia

Objective: To assess the association of intrauterine insemination, in vitro fertilization (IVF) and ovulation induction with the risk of preeclampsia. Methods: We conducted a population based retrospective cohort study of pregnancies conceived by assisted reproductive technology (1357 exposure subjects, 5190 controls) based on 2005 Niday Perinatal Database for Ontario, Canada. All pregnancies conceived by assisted reproductive technology were identified as exposure group. Four controls were randomly matched for each exposure subject by maternal age, parity, plurality, and delivery hospital level and residence area. The risks for preeclampsia associated with intrauterine insemination, IVF, and ovulation induction were evaluated through conditional logistic regression models compared with their corresponding controls. Results: With adjustment of maternal age, smoking during pregnancy and initiating time of prenatal care, in vitro fertilization was associated with an increased risk for preeclampsia (OR = 1.78, 95% CI: 1.05, 3.06), whereas intrauterine insemination (OR = 2.44, 95% CI: 0.74, 8.06) and ovulation induction (OR = 1.34, 95% CI: 0.31, 5.75) was not associated with the risk for preeclampsia. Conclusion: There was a higher incidence of preeclampsia among pregnancies conceived by IVF, but no significant association was found in intrauterine insemination and ovulation induction.

Hypertensive Disorders of Pregnancy and Long-Term Risk of Hypertension: What Do Ontario Prenatal Care Providers Know and What Do They Communicate?

OBJECTIVES The objective of this study was to ascertain the knowledge base of Ontario maternity care providers (family physicians, obstetrician-gynaecologists, and midwives) regarding the future health risks of gestational hypertension and preeclampsia and the practices with respect to communication of these risks. METHODS In 2004, all obstetricians (639) and midwives (249) in Ontario and a random sample of 600 Ontario family physicians were mailed a survey and a reminder. Non-responders were also sent a second, and in some cases, a third copy of the survey. The survey addressed areas of knowledge, reported practices, and both patient and interprofessional communication. Descriptive analysis was used for the responses. RESULTS The overall response rate was 42%. The majority of respondents were familiar with the long-term risks of gestational hypertension and preeclampsia. Although maternity care providers stated that they inform women with these conditions about their subsequent risks and recommend follow-up, only 36% usually inform the womens primary care providers about that subsequent risk. Only 58% of family physicians reported that they are usually informed by the maternity care providers about their patients who developed hypertension in pregnancy, compared with the 83% of maternity care providers who reported that they usually communicate this information to family physicians. CONCLUSION We have identified weaknesses in knowledge base and communication amongst Ontario maternity care providers that suggest that the identification and follow-up of women with hypertensive disorders of pregnancy is not occurring. These deficiencies would be amenable to directed educational activities, including reviews, presentations, and the development and implementation of guidelines.

Pregnancy‐induced hypertension and infant mortality: roles of birthweight centiles and gestational age

Objective  To assess the effect of pregnancy‐induced hypertension (PIH) on infant mortality in different birthweight centiles (small for gestational age [SGA], appropriate for gestational age [AGA], and large for gestational age [LGA]) and gestational ages (early preterm, late preterm, and full term).

Perinatal outcomes of normal cotwins in twin pregnancies with one structurally anomalous fetus: a population-based retrospective study.

We examined the impact of the presence of one anomalous fetus in a twin pregnancy on perinatal outcomes in the normal cotwin. Perinatal outcomes in cotwins with an anomalous twin and cotwins without an anomalous twin were compared using data from the 1995 to 1997 United States Matched Multiple Births dataset. The two groups were matched by maternal age, parity, birth order, gender, and sex concordance (1:4 matching). The risks of preterm birth, low birth weight, small-for-gestational-age birth, fetal distress, the use of assisted ventilation, low Apgar score, fetal death, neonatal death, and infant death in the 3307 normal cotwins with a twin affected by structural anomalies were significantly higher than those of the 12,813 matched cotwins without an anomalous twin. The presence of one structurally anomalous fetus in a twin pregnancy increases the risks of adverse perinatal outcomes in the cotwin without a fetal anomaly.

Recent oral contraceptive use and adverse birth outcomes

OBJECTIVE To examine the possible association between oral contraceptive use and adverse birth outcomes. STUDY DESIGN We conducted a population-based cohort study of pregnant women who used oral contraceptives within 3 months before their last menstrual period. Subjects were divided into three groups, according to the interval (0-30, 31-60, and 61-90 days) between the dispensing date and their last menstrual period. For each exposed subject, 4 subjects without exposure to oral contraceptives were individually matched by infants year of birth and plurality and by mothers age and parity. RESULTS Oral contraceptive use within 30 days prior to the last menstrual period was associated with increased risks of very low birth weight (OR: 3.24, 95% CI: 1.18, 8.92), low birth weight (OR: 1.93, 95% CI: 1.17, 3.20), and preterm birth (OR: 1.61, 95% CI: 1.01, 2.55); however, oral contraceptive use 31-90 days prior to the last menstrual period did not increase the risk of low birth weight or preterm birth. CONCLUSION Our results indicate the use of oral contraceptives near the time of conception may be associated with an increased risk of low birth weight and preterm birth.