Clinical birthweight standards for a total population in the 1980s

Association of acetaminophen use with perinatal outcomes among pregnant women: a retrospective cohort study with propensity score matching

BACKGROUND

Although acetaminophen is widely used in women during pregnancy, its safety has not been clearly stated. The study aimed to investigate the association between acetaminophen use and adverse pregnancy outcomes in pregnant women in China.

METHODS

We conducted a retrospective cohort study by collecting data on pregnant women who delivered in the Beijing Obstetrics and Gynecology Hospital from January 2018 to September 2023. An acetaminophen use group and a control group were formed based on prenatal exposure to acetaminophen. The pregnancy outcomes that we focused on were stillbirth, miscarriage, preterm birth, APGAR score, birth weight, and congenital disabilities. Pregnant women exposed to acetaminophen were matched to unexposed in a 1:1 ratio with propensity score matching, using the greedy matching macro. SPSS software was used for statistical analysis. Multivariable logistics regression was used to assess the association between acetaminophen use during pregnancy and adverse pregnancy outcomes.

RESULTS

A total of 41,440 pregnant women were included, of whom 501 were exposed to acetaminophen during pregnancy, and 40,939 were not exposed. After the propensity score matching, the acetaminophen use and control groups consisted of 501 pregnant women each. The primary analysis showed that acetaminophen exposure during pregnancy was associated with an increased risk of stillbirth (adjusted OR (aOR) = 2.29, 95% CI, 1.19-4.43), APGAR score < 7 at 1 min (aOR = 3.28, 95% CI, 1.73-6.21), APGAR score < 7 at 5 min (aOR = 3.54, 95% CI, 1.74-7.20), APGAR score < 7 at 10 min (aOR = 3.18, 95% CI, 1.58-6.41), and high birth weight (HBW) (aOR = 1.75, 95% CI, 1.05-2.92). Drug exposure during the first and second trimesters increased the odds of stillbirth, miscarriage, APGAR < 7, and the occurrence of at least one adverse pregnancy outcome. In addition, the frequency of drug use more than two times was associated with a higher risk of preterm birth and APGAR score < 7.

CONCLUSIONS

Exposure to acetaminophen during pregnancy was significantly associated with the occurrence of adverse pregnancy outcomes, particularly exposure in the first and second trimesters and frequency of use more than twice. It is suggested that acetaminophen should be prescribed with caution in pregnant women.

Maternal over-the-counter analgesics use during pregnancy and adverse perinatal outcomes: cohort study of 151 141 singleton pregnancies

OBJECTIVES

To identify any associations between in utero exposure to five over-the-counter (non-prescription) analgesics (paracetamol, ibuprofen, aspirin, diclofenac, naproxen) and adverse neonatal outcomes.

DESIGN

Retrospective cohort study using the Aberdeen Maternity and Neonatal Databank.

PARTICIPANTS

151 141 singleton pregnancies between 1985 and 2015.

MAIN OUTCOME MEASURES

Premature delivery (<37 weeks), stillbirth, neonatal death, birth weight, standardised birthweight score, neonatal unit admission, APGAR score at 1 and 5 min, neural tube and amniotic band defects, gastroschisis and, in males, cryptorchidism and hypospadias.

RESULTS

83.7% of women taking over-the-counter analgesics reported first trimester use when specifically asked about use at their first antenatal clinic visit. Pregnancies exposed to at least one of the five analgesics were significantly independently associated with increased risks for premature delivery <37 weeks (adjusted OR (aOR)=1.50, 95% CI 1.43 to 1.58), stillbirth (aOR=1.33, 95% CI 1.15 to 1.54), neonatal death (aOR=1.56, 95% CI 1.27 to 1.93), birth weight <2500 g (aOR=1.28, 95% CI 1.20 to 1.37), birth weight >4000 g (aOR=1.09, 95% CI 1.05 to 1.13), admission to neonatal unit (aOR=1.57, 95% CI 1.51 to 1.64), APGAR score <7 at 1 min (aOR=1.18, 95% CI 1.13 to 1.23) and 5 min (aOR=1.48, 95% CI 1.35 to 1.62), neural tube defects (aOR=1.64, 95% CI 1.08 to 2.47) and hypospadias (aOR=1.27, 95% CI 1.05 to 1.54 males only). The overall prevalence of over-the-counter analgesics use during pregnancy was 29.1%, however it rapidly increased over the 30-year study period, to include over 60% of women in the last 7 years of the study. This makes our findings highly relevant to the wider pregnant population.

CONCLUSIONS

Over-the-counter (non-prescription) analgesics consumption during pregnancy was associated with a substantially higher risk for adverse perinatal health outcomes in the offspring. The use of paracetamol in combination with other non-steroidal anti-inflammatory drugs conferred the highest risk. The increased risks of adverse neonatal outcomes associated with non-prescribed, over-the-counter, analgesics use during pregnancy indicate that healthcare guidance for pregnant women regarding analgesic use need urgent updating.

Weight change across the start of three consecutive pregnancies and the risk of maternal morbidity and SGA birth at the second and third pregnancy

BACKGROUND

Weight-change across parities and/or current BMI may influence maternal and fetal morbidity and requires to be differentiated to better inform weight-management guidance.

METHODS

Direction, pattern and magnitude of weight-change across three consecutive parities and thereby two inter-pregnancy periods was described in 5079 women. The association between inter-pregnancy weight-change versus current BMI and adverse maternal events, SGA-birth and preterm delivery at second and third pregnancy were investigated by logistic regression.

RESULTS

More women gained weight across the defined childbearing period than lost it, with ~35% of normal and overweight women gaining sufficient weight to move up a BMI-category. Nine patterns of weight-change were defined across two inter-pregnancy periods and 50% of women remained weight-stable throughout (within 2BMI units/period). Women who were overweight/obese at first pregnancy had higher risk of substantial weight-gain and loss (>10kg) during each of two inter-pregnancy periods. Inter-pregnancy weight-gain (> 2BMI units) between first and second pregnancy increased the risk of maternal morbidity (1or more event of hypertensive disease, caesarean-section, thromboembolism) at second pregnancy, while weight-loss (>2BMI units) increased the risk of SGA-birth. Similarly, increased risk of maternal morbidity at the third pregnancy was influenced by weight-gain during both inter-pregnancy periods but not by current BMI-category. Both weight-gain between first and second pregnancy, and being overweight/obese by third pregnancy protected the fetus against SGA-birth whereas weight-loss between second and third pregnancy doubled the SGA risk.

CONCLUSION

Half the women studied exhibited significant weight-fluctuations. This influenced their risk of maternal morbidity and SGA-birth at second and third pregnancy.

Maternal gestational weight gain and offspring's risk of cardiovascular disease and mortality

OBJECTIVE

To examine the effect of maternal gestational weight gain (GWG) on adult offspring mortality, cardiovascular morbidity and cerebrovascular morbidity.

METHODS

The Aberdeen Children of the Nineteen Fifties (ACONF) is a population-based cohort of adults born in Aberdeen, Scotland between 1950 and 1956. GWG of the mothers of cohort members was extracted from original birth records and linked to the data on offspring morbidity and mortality up to 2011 obtained from Scottish national records. HRs for cardiovascular events and mortality in offspring according to maternal weight gain in pregnancy were estimated adjusting for maternal and offspring confounders using a restricted cubic spline model.

RESULTS

After exclusions, 3781 members of the original ACONF cohort were analysed. Of these, 103 (2.7%) had died, 169 (4.5%) had suffered at least one cardiovascular event and 73 (1.9%) had had a hospital admission for cerebrovascular disease. Maternal weight gain of 1 kg/week or more was associated with increased risk of cerebrovascular event in the offspring (adjusted HR 2.70 (95% CI 1.19 to 6.12)). There was no association seen between GWG and offspring's all-cause mortality or cardiovascular event. Adult offspring characteristics (smoking, body mass index (BMI) and diabetes) were strongly associated with each outcome.

CONCLUSIONS

Maternal GWG above 0.9 kg/week may increase the risk of cerebrovascular disease in the adult offspring, but not all-cause mortality or cardiovascular disease. Health and lifestyle factors such as smoking, BMI and diabetes in the adult offspring had a stronger influence than maternal and birth characteristics on their mortality and morbidity.

Inter-Pregnancy Weight Change and the Risk of Recurrent Pregnancy Complications

Women with specific adverse pregnancy outcomes in their first pregnancy may be receptive to inter-pregnancy weight management guidance aimed at preventing these complications reoccurring in subsequent pregnancies. Thus the association between inter-pregnancy weight change and the risk of recurrent pregnancy complications at the second pregnancy was investigated in a retrospective cohort study of 24,520 women with their first-ever and second consecutive deliveries in Aberdeen using logistic regression. Compared with women who were weight stable, weight loss (>2BMI units) between pregnancies was associated with an increased risk of recurrent small for gestational age (SGA) birth and elective Cesarean-section, and was protective against recurrent pre-eclampsia, placental oversize and large for gestational age (LGA) birth. Conversely weight gain (>2BMI units) between pregnancies increased the risk of recurrent gestational hypertension, placental oversize and LGA birth and was protective against recurrent low placental weight and SGA birth. The relationships between weight gain, and placental and birth weight extremes were evident only in women with a healthy weight at first pregnancy (BMI<25units), while that between weight gain and the increased risk of recurrent gestational hypertension was largely independent of first pregnancy BMI. No relationship was detected between inter-pregnancy weight change and the risk of recurrent spontaneous preterm delivery, labour induction, instrumental delivery, emergency Cesarean-section or postpartum hemorrhage. Therefor inter-pregnancy weight change impacts the risk of recurrent hypertensive disorders, SGA and LGA birth and women with a prior history of these specific conditions may benefit from targeted nutritional advice to either lose or gain weight after their first pregnancy.

Exploring the relationship between maternal body mass index and offspring birth weight: Analysis of routinely collected data from 1967 to 2010 in Aberdeen, Scotland

A retrospective cohort study was undertaken to assess the relationship between maternal body mass index (BMI) and neonatal birth weight. Data were extracted from Aberdeen Maternity and Neonatal Databank on all deliveries (n = 94049) occurring between 1967 and 2010. Compared with mothers whose weight was in the normal range, the adjusted odds of delivering a high-birth-weight infant were 0.63 (95% confidence interval: 0.59, 0.67), 1.44 (1.39, 1.50); 1.83 (1.72, 1.95); 2.22 (2.04, 2.43) in underweight, overweight, obese and morbidly obese mothers, respectively. Similarly, the adjusted odds of delivering a low-birth-weight baby decreased with increasing maternal BMI from 1.38 (1.23, 1.55) in underweight women to 0.80 (0.72, 0.89) in overweight women; 0.78 (0.67, 0.93) in obese and 0.56 (0.44, 0.71) in morbidly obese mothers. These relationships were only evident after adjustment for gestational age, presumably because higher maternal BMI is also, in some cases, associated with pre-term deliveries.

Inter-pregnancy weight change impacts placental weight and is associated with the risk of adverse pregnancy outcomes in the second pregnancy

BACKGROUND

The inter-pregnancy period is considered a teachable moment when women are receptive to weight- management guidance aimed at optimising pregnancy outcome in subsequent pregnancies. In population based studies inter-pregnancy weight change is associated with several adverse pregnancy outcomes but the impact on placental size is unknown.

METHODS

The association between inter-pregnancy weight change and the primary risk of adverse pregnancy outcomes in the second pregnancy was investigated in 12,740 women with first two consecutive deliveries at a single hospital using logistic regression.

RESULTS

Compared with women who were weight stable, weight loss (>1BMI unit) between pregnancies was associated with an increased risk of spontaneous preterm delivery, low placental weight and small for gestational age (SGA) birth, while weight gain (>3BMI units) increased the risk of pre-eclampsia, gestational hypertension, emergency caesarean section, placental oversize and large for gestational age (LGA) birth at the second pregnancy. The relationship between weight gain and pre-eclampsia risk was evident in women who were overweight at first pregnancy only (BMI ≥25 units), while that between weight loss and preterm delivery was confined to women with a healthy weight at first pregnancy (BMI <25 units). In contrast, the association between weight loss and SGA was independent of first pregnancy BMI. A higher percentage of women who were obese at first pregnancy were likely to experience a large weight gain (P < 0.01) or weight loss (P < 0.001) between consecutive pregnancies compared with the normal BMI reference group.

CONCLUSION

Inter-pregnancy weight change in either direction increases the risk of a number of contrasting pregnancy complications, including extremes of placental weight. The placenta may lie on the causal pathway between BMI change and the risk of LGA or SGA birth.

Maternal and perinatal risk factors for childhood cancer: record linkage study

OBJECTIVE

To investigate maternal and perinatal risk factors for childhood cancer.

STUDY DESIGN

Case-control analysis of linked records from the Aberdeen Maternity and Neonatal Databank with the Scottish Cancer Registry and the General Registry of Births and Deaths in Scotland was carried out.

SETTING

Aberdeen, Scotland.

PARTICIPANTS

Cases (n=176) comprised children diagnosed with cancer under 15 years or recorded as having died of cancer. Four controls per case were matched by age and gender.

RISK FACTORS TESTED

Maternal age, body mass index, social class, marital status and smoking as well as pre-eclampsia, antepartum haemorrhage and previous miscarriage, gestational age, birth weight and Apgar scores were compared between groups to test for association with cancer. ORs with 95% CIs were calculated using conditional logistic regression in univariable and multivariable models.

RESULTS

Of the maternal characteristics tested, mother's age at delivery (cases mean 28.9 (SD 5.6) years vs controls mean 30.2 (SD 4.6), p=0.002) and smoking status (38.6% smokers among cases, 29.7% among controls, p=0.034) were found to be different between groups. Of the perinatal factors tested, low Apgar score at 5 min (adjusted OR (AOR) 4.59, 95% CI 1.52 to 13.87) and delivery by caesarean section (AOR 1.95, 95% CI 1.30 to 2.92) showed statistically significant associations with childhood cancer in the multivariable model.

CONCLUSIONS

Younger maternal age, maternal smoking, delivery by caesarean section and low Apgar score at 5 min were independently associated with increased risk of childhood cancer. These general findings should be interpreted with caution as this study did not have the power to detect any association with individual diagnostic categories of childhood cancer.

DNA methyltransferase candidate polymorphisms, imprinting methylation, and birth outcome

Background

Birth weight and prematurity are important obstetric outcomes linked to lifelong health. We studied a large birth cohort to look for evidence of epigenetic involvement in birth outcomes.

Methods

We investigated the association between birth weight, length, placental weight and duration of gestation and four candidate variants in 1,236 mothers and 1,073 newborns; DNMT1 (rs2162560), DNMT3A (rs734693), DNMT3B (rs2424913) and DNMT3L (rs7354779). We measured methylation of LINE1 and the imprinted genes, PEG3, SNRPN, and IGF2, in cord blood.

Results

The minor DNMT3L allele in the baby was associated with higher birth weight (+54 95% CI 10,99 g; p = 0.016), birth length (+0.23 95% CI 0.04,0.42 cm; p = 0.017), placental weight, (+18 95% CI 3,33 g; p = 0.017), and reduced risk of being in the lowest birth weight decile (p = 0.018) or requiring neonatal care (p = 0.039). The DNMT3B minor allele in the mother was associated with an increased risk of prematurity (p = 0.001). Placental size was related to PEG3 (p<0.001) and IGF2 (p<0.001) methylation. Birth weight was related to LINE1 and IGF2 methylation but only at p = 0.052. The risk of requiring neonatal treatment was related to LINE1 (p = 0.010) and SNRPN (p = 0.001) methylation. PEG3 methylation was influenced by baby DNMT3A genotype (p = 0.012) and LINE1 by baby 3B genotype (p = 0.044). Maternal DNMT3L genotype was related to IGF2 methylation in the cord blood but this effect was only seen in carriers of the minor frequency allele (p = 0.050).

Conclusions

The results here suggest that epigenetic processes are linked birth outcome and health in early life. Our emerging understanding of the role of epigenetics in health and biological function across the lifecourse suggests that these early epigenetic events could have longer term implications.

Outcomes of pregnancy in women using illegal drugs and in women who smoke cigarettes

OBJECTIVE

To compare obstetric outcomes in women using illegal drugs with women who smoke cigarettes.

DESIGN

Retrospective cohort study.

SETTING

Aberdeen, UK.

POPULATION

All deliveries in Aberdeen in women using illegal drugs and women who smoked cigarettes during 1997-2007.

MATERIAL AND METHODS

The women who used illegal drugs were identified from a database of affected pregnant women in Aberdeen. The Aberdeen Maternity and Neonatal Databank was used to identify women who smoke cigarettes and to obtain pregnancy outcome information. Sociodemographic characteristics, maternal and perinatal outcomes were compared using chi-squared test, independent sample t-test and logistic regression analysis.

MAIN OUTCOME MEASURES

Preterm delivery, low birthweight (standardized birthweight score <-2) and admission to the neonatal unit.

RESULTS

Of the 561 illegal drug users, 96% were also cigarette smokers. Compared with women who smoke cigarettes with no reported illegal drug use, they were significantly more likely to have a preterm delivery [adjusted odds ratio (aOR) 1.6 (95% confidence interval (CI) 1.3-2.1)], low birthweight baby [aOR 1.9 (95%CI 1.4-2.6)], baby admitted to the neonatal unit [aOR 13.3 (95%CI 10.9-16.3)], deep vein thrombosis [aOR (95%CI 8.8-50.8)] and antepartum hemorrhage [aOR (95%CI 1.2-2.1)]. They were less likely to be at the extremes of age, or to develop pregnancy-induced hypertension [aOR 0.3 (95%CI 0.2-0.4)].

CONCLUSION

Illegal drug use in pregnancy appears to increase the risk of adverse outcomes, over and above that related to cigarette smoking, but appears to be associated with lower prevalence of gestational hypertension.

Folate in pregnancy and imprinted gene and repeat element methylation in the offspring

BACKGROUND

Epigenetic regulation of imprinted genes and transposable elements has been implicated in human disease and may be affected by maternal diet.

OBJECTIVE

The objective was to determine the effect on offspring epigenetic status of nutritional and genetic factors that influence folate exposure in pregnancy.

DESIGN

We measured folate intake from diet, the use of folic acid supplements and the period of consumption, maternal and cord red blood cell (RBC) folate, and genotypes for 5 methylation cycle enzymes in a prospective cohort study of pregnancies in the United Kingdom between 2000 and 2006. We related these to offspring methylation status within 3 maternally methylated imprinted genes: paternally expressed gene 3 (PEG3), insulin-like growth factor 2 (IGF2), and small nuclear ribonucleoprotein polypeptide N, and the long interspersed nuclear element 1 (LINE-1) in genomic DNA extracted from whole blood in 913 pregnancies.

RESULTS

Supplement use after 12 wk of gestation was associated with a higher level of methylation in IGF2 (+0.7%; 95% CI: 0.02, 1.4; P = 0.044) and reduced methylation in both PEG3 (-0.5%; 95% CI: -0.9, -0.1; P = 0.018) and LINE-1 (-0.3%; 95% CI: -0.6, -0.04; P = 0.029). The same pattern was observed in relation to RBC folate in the cord blood at birth: IGF2 (P = 0.038), PEG3 (P < 0.001), and LINE-1 (P < 0.001). LINE-1 methylation was related to maternal RBC folate (P = 0.001) at 19 wk. No effect of supplement use up to 12 wk (current recommendation) was found.

CONCLUSIONS

Folic acid use after 12 wk of gestation influences offspring repeat element and imprinted gene methylation. We need to understand the consequences of these epigenetic effects.

Pregnancy outcomes of women with and without a history of anorexia nervosa

BACKGROUND

When women have a history of anorexia nervosa (AN), the advice given about becoming pregnant, and about the management of pregnancies, has usually been cautious. This study compared the pregnancy outcomes of women with and without a history of AN.

METHOD

Women with a confirmed diagnosis of AN who had presented to psychiatric services in North East Scotland from 1965 to 2007 were identified. Those women with a pregnancy recorded in the Aberdeen Maternal and Neonatal Databank (AMND) were each matched by age, parity and year of delivery of their first baby with five women with no history of AN. Maternal and foetal outcomes were compared between these two groups of women. Comparisons were also made between the mothers with a history of AN and all other women in the AMND.

RESULTS

A total of 134 women with a history of AN delivered 230 babies and the 670 matched women delivered 1144 babies. Mothers with AN delivered lighter babies but this difference did not persist after adjusting for maternal body mass index (BMI) in early pregnancy. Standardized birthweight (SBW) scores suggested that the AN mothers were more likely to produce babies with intrauterine growth restriction (IUGR) [relative risk (RR) 1.54, 95% confidence interval (CI) 1.11-2.13]. AN mothers were more likely to experience antepartum haemorrhage (RR 1.70, 95% CI 1.09-2.65).

CONCLUSIONS

Mothers with a history of AN are at increased risk of adverse pregnancy outcomes. The magnitude of these risks is relatively small and should be appraised holistically by psychiatric and obstetric services.

Vitamin D in pregnancy at high latitude in Scotland

The aims of the present study were to determine compliance with current advice on vitamin D and to assess the influence of season, dietary intake, supplement use and deprivation on vitamin D status in pregnant mothers and newborns in the north of Scotland where sunlight exposure is low. Pregnant women (n 1205) and their singleton newborns were studied in the Aberdeen Maternity Hospital (latitude 57°N) between 2000 and 2006. Plasma 25-hydroxyvitamin D2 and 25-hydroxyvitamin D3 were measured at 19 weeks of gestation in mothers and at delivery in newborns. During pregnancy, 21·0 (95 % CI 18·5, 23·5) % of women took vitamin D supplements. The median intake was 5 μg/d and only 0·6 (95 % CI 0·1, 1·0) % took the recommended 10 μg/d. Supplement use, adjusted for season, dietary intake and deprivation, significantly increased maternal 25-hydroxyvitamin D (25(OH)D) by 10·5 (95 % CI 5·7, 15·2) nmol/l (P< 0·001); however, there was no significant effect on cord 25(OH)D (1·4 (95 % CI - 1·8, 4·5) nmol/l). The biggest influence on both maternal and cord 25(OH)D was season of birth (P< 0·001). Compared with the least deprived women (top three deciles), the most deprived pregnancies (bottom three deciles) were characterised by a significantly lower seasonally adjusted 25(OH)D ( - 11·6 (95 % CI - 7·5, - 15·7) nmol/l in the mother and - 5·8 (95 % CI - 2·3, - 9·4) nmol/l in the cord), and a lower level of supplement use (10 (95 % CI 4, 17) v. 23 (95 % CI 20, 26) %). More should be done to promote vitamin D supplement use in pregnancy but the critical importance of endogenous vitamin D synthesis, and known adaptations of fat metabolism specific to pregnancy, suggest that safe sun advice may be a useful additional strategy, even at high latitude.

Diet and deprivation in pregnancy

Deprivation is associated with poor pregnancy outcome but the role of nutrition as a mediating factor is not well understood. We carried out a prospective cohort study of 1461 singleton pregnancies in Aberdeen, UK during 2000-6. We measured nutrient intake and supplement use, B vitamin and homocysteine status, birth weight, gestational age, neonatal treatment and socio-economic deprivation status. Women in the most deprived deciles were approximately 6 years younger and half as likely to take folic acid supplements periconceptually as the least deprived mothers. Deprivation was associated with low blood folate, high homocysteine and diets low in protein, fibre and many of the vitamins and minerals. The diets of the more deprived women were also characterised by low intakes of fruit, vegetables and oily fish and higher intakes of processed meat, fried potatoes, crisps and snacks. Deprivation was related to preterm birth (OR 1.14 (95 % CI 1.03, 1.25); P = 0.009) and whether the baby required neonatal treatment (OR 1.07 (95 % CI 1.01, 1.14); P = 0.028). Low birth weight was more common in women consuming diets low in vitamin C (OR 0.79 (95 % CI 0.64, 0.97); P = 0.028), riboflavin (OR 0.77 (95 % CI 0.63, 0.93); P = 0.008), pantothenic acid (OR 0.79 (95 % CI 0.65, 0.97); P = 0.023) and sugars (OR 0.78 (95 % CI 0.64, 0.96); P = 0.017) even after adjustment for deprivation index, smoking, marital status and parity. Deprivation in pregnancy is associated with diets poor in specific nutrients and poor diet appears to contribute to inequalities in pregnancy outcome. Improving the nutrient intake of disadvantaged women of childbearing age may potentially improve pregnancy outcome.

Centile charts for birthweight for gestational age for Scottish singleton births

BACKGROUND

Centile charts of birthweight for gestational age are used to identify low birthweight babies. The charts currently used in Scotland are based on data from the 1970s and require updating given changes in birthweight and in the measurement of gestational age since then.

METHODS

Routinely collected data of 100,133 singleton births occurring in Scotland from 1998-2003 were used to construct new centile charts using the LMS method.

RESULTS

Centile charts for birthweight for sex and parity groupings were constructed for singleton birth and compared to existing charts used in Scottish hospitals.

CONCLUSION

Mean birthweight has been shown to have increased over recent decades. The differences shown between the new and currently used centiles confirm the need for more up-to-date centiles for birthweight for gestational age.

Intrauterine growth standards in a developing country: a study of singleton livebirths at 28-42 weeks' gestation

This study aimed to develop fetal growth charts for the population of Greater Beirut, Lebanon, and compare them with previously established references. A survey of consecutive singleton livebirths admitted to normal nurseries and neonatal intensive care units of major hospitals, through the database project of the National Collaborative Perinatal Neonatal Network was used as a design. The study was conducted in nine major healthcare institutions serving the population of Beirut and its suburbs. A total of 24 767 singleton livebirths delivered between 28 and 42 weeks' gestation, with known data on gender, gestational age and anthropometric characteristics were recorded between 1 April 1999 and 31 March 2002. Growth charts were developed by plotting birthweight, length and head circumference percentiles against gestational age for male and female infants separately. Overall, 1348 (5.4%) pregnancies were delivered before 37 weeks' gestation and 1227 (4.9%) were low birthweight. Male infants were delivered slightly earlier than their female counterparts and the mean birthweight, length and head circumference were consistently higher in males. A total of 2247 (9.1%) infants were small-for-gestational-age, with a male-to-female sex ratio of 1.03. Using previously established growth references that overestimated small-for-gestational-age prevalence resulted in a greater proportion of false positives. The opposite was true for growth references that underestimated small-for-gestational-age prevalence. The current growth charts present useful tools for assessing the general health status of newborn infants delivered at sea level in the urban areas of Lebanon and other East Mediterranean countries.

Obstetric Outcome in Women With Threatened Miscarriage in the First Trimester

OBJECTIVE

To assess pregnancy outcomes in women with threatened miscarriage in the first trimester.

METHODS

This was a retrospective cohort study based on data extracted from the Aberdeen Maternity and Neonatal Databank. Cases included all primigravid women with first-trimester vaginal bleeding who delivered after 24 weeks of gestation between 1976 and 2004. The control group comprised all other women who had first pregnancies during the same period. Data were analyzed by univariate and multivariate statistical methods.

RESULTS

Compared with the control group (n = 31,633), women with threatened miscarriage (n = 7,627) were more likely to have antepartum hemorrhage of unknown origin (odds ratio [OR] 1.83, 95% confidence interval [CI] 1.73-2.01). Elective cesarean (OR 1.30, 95% CI 1.14-1.48) and manual removal of placenta (OR 1.40, 95% CI 1.21-1.62) were performed more frequently in these women, who also had a higher risk of preterm delivery (OR 1.56, 95% CI 1.43-1.71) and malpresentation (OR 1.26, 95% CI 1.13-1.40). Threatened miscarriage in the first trimester is required in 112, 112, 17, 85, 32 patients, respectively, for each additional case of manual removal of placenta, elective cesarean, antepartum hemorrhage of unknown origin, malpresentation, and preterm delivery.

CONCLUSION

Pregnancies complicated by threatened miscarriage are at a slightly higher risk of obstetric complications and interventions.

LEVEL OF EVIDENCE

II-2.

Obstetric outcome in women with subfertility

BACKGROUND

It has been suggested that a history of subfertility is associated with increased obstetric and perinatal risks. It is unclear if the cause is inherent characteristics in the women or the fertility treatment.

OBJECTIVES

To compare the obstetric and perinatal risks of singleton pregnancies in women with a history of subfertility in comparison with the general population.

DESIGN

Population cohort.

SETTING

Aberdeen, Scotland.

POPULATION

Cases were women attending the Fertility Clinic between 1989 and 1999 who subsequently went on to have singleton pregnancies. Controls included the general population of women who delivered singletons over the same period.

METHODS

We performed a retrospective cohort study to investigate the obstetric outcome of singleton pregnancies in women with subfertility. The general population of women who delivered singletons over the same period served as controls.

MAIN OUTCOME MEASURES

Obstetric and perinatal complications in singleton pregnancies.

RESULTS

Maternity records were available for a total of 1437 subfertile women and 21,688 controls. Subfertile women were older [mean (SD) age: 31 (4.7) years vs 27 (5.4) years, P < 0.01] and more likely to be primiparous (70% vs 65%, P < 0.001). After adjusting for age and parity, subfertile women were at increased risk of pre-eclampsia (OR 1.9, 95% CI 1.5-2.5), placenta praevia (OR 3.9, 95% CI 2.2-7.0) and placental abruption (OR 1.8, 95% CI 1.1-3.0), and more likely to undergo induction of labour (OR 1.5, 95% CI 1.3-1.6), caesarean section (OR 2.1, 95% CI 1.8-2.4) and instrumental delivery (OR 2.2, 95% CI 1.8-2.6), and deliver low birthweight (OR 1.4, 95% CI 1.3-1.7) and preterm (OR 1.7, 95% CI 1.2-2.2) infants. There were no differences between treatment-related and treatment-independent pregnancies.

CONCLUSION

Subfertile women are at higher risk of obstetric complications, which persist after adjusting for age and parity.

Birthweight by gestational age in preterm babies according to a Gaussian mixture model

OBJECTIVE

To provide a statistically sound criterion for identifying implausibly large birthweights for gestational age.

DESIGN

Review of ISTAT 1990-1994 national newborn records.

SETTING

Italy

POPULATION

Forty-two thousand and twenty-nine single first and second liveborn preterm babies.

METHODS

Two-component Gaussian mixture models are used to describe the birthweight distributions stratified by gestational age. Implausibly large babies are identified through model-based probabilistic clustering.

MAIN OUTCOME MEASURES

Gestational age misclassification and weight-for-gestational age centile curves

RESULTS

Gestational age appears under-estimated by about six weeks in 12.3% of the cases. Large babies are equally present in males and females, but are more frequent in second-borns than in first-borns, even when parity-specific models are fitted.

CONCLUSIONS

The approach allows for a quantification of the gestational age under-estimate error and for data correction through model-based clustering. Correct birthweight distributions and growth curves are also provided.

Relationship between birth weight and adult lung function: controlling for maternal factors

BACKGROUND

There is conflicting evidence on the "fetal origins hypothesis" of association between birth weight and adult lung function. This may be due to failure to control for confounding maternal factors influencing birth weight. In the present study access to birth details for adults aged 45-50 years who were documented as children to have asthma, wheezy bronchitis, or no respiratory symptoms provided an opportunity to investigate this association, controlling for maternal factors.

METHODS

In 2001 the cohort was assessed for current lung function, smoking status, and respiratory symptoms. Birth details obtained from the Aberdeen Maternity and Neonatal Databank recorded birth weight, gestation, parity, and mother's age and height.

RESULTS

381 subjects aged 45-50 years were traced and tested for lung function; 323 (85%) had birth details available. A significant linear trend (p<0.01) was observed between birth weight and current forced expiratory volume in 1 second (FEV(1)) and forced vital capacity (FVC) values (adjusted for height, age, sex, weight, deprivation category (Depcat), childhood group, and smoking status). This trend remained significant after adjusting birth weight for gestation, parity, sex, mother's height and weight (p = 0.01). The relationship between birth weight and FEV(1) and FVC remained significant when adjusted for smoking history. There was no association between birth weight and current wheezing symptoms.

CONCLUSION

There is a positive linear trend between birth weight, adjusted for maternal factors, and lung function in adulthood. The strength of this association supports the "fetal origins hypothesis" that impairment of fetal growth is a significant influence on adult lung function.

Antenatal factors in the development of the lumbar vertebral canal: a magnetic resonance imaging study

STUDY DESIGN

The lumbar vertebral canal was measured in two cohorts of 10-year-old children (n = 161) using magnetic resonance imaging (MRI) and compared with obstetric records.

OBJECTIVE

To investigate whether there are identifiable obstetric factors that determine the size of the lumbar vertebral canal.

SUMMARY OF BACKGROUND DATA

The most rapid period growth for the lumbar vertebral canal is between 12 and 32 weeks in utero, with the midsagittal diameter of L1-L4 already 70% of adult dimension at birth. Therefore, adverse antenatal factors during this critical growth period may be expected to affect the size of the canal.

METHODS

The canal size was measured from axial MRI sections taken through each lumbar vertebra (L1-L5) at the pedicular level of 84 children. Relations with obstetric data, prospectively collected in a neonatal database, were sought. The relation of low birthweight and canal size was further investigated in a second cohort of children (n = 77).

RESULTS

The canal size, particularly the midsagittal diameter and the cross-sectional area, was found to be significantly reduced by low birthweight (with growth retardation in utero being a more important factor than length of gestation), low placenta weight, and lower socioeconomic class. Smoking during pregnancy significantly reduced the perimeter at L3 (P = 0.032) and L5 (P = 0.031), and also the cross-sectional area at L3 (P = 0.030) and L5 (P = 0.016).

CONCLUSIONS

This study showed that, for this group of children, the size of the lumbar vertebral canal was reduced by low birthweight, with maternal smoking as an added adverse factor. Therefore, good antenatal care and maternal education may help to reduce the risk of spinal stenosis in adult life.

The relationship between birth weight and maternal glycated haemoglobin (HbA1c) concentration in pregnancies complicated by Type 1 diabetes

AIM

To examine the relationships between maternal HbA1c concentration at different time points and birth weight in pregnancies complicated by pre-existing Type 1 diabetes.

METHODS

A comprehensive audit dataset was collected prospectively on all deliveries in Scotland to women with pre-existing Type 1 diabetes occurring between 1 April 1998 and 31 March 1999. Data items included HbA1c concentrations prior to conception and in each of the three trimesters of pregnancy, and birth weight. Relationships between standardized birth weight and HbA1c concentrations at each of the four time points were examined using correlation analysis.

RESULTS

Standardized birth weight (Z scores) could be calculated for 203 of 208 singleton liveborn infants. HbA1c concentrations, standardized to correct for assay differences among hospitals, at different time points were available for between 134 (pre-pregnancy) and 192 (third trimester) cases. Standardized birth weight, relative to a reference population, showed a unimodal distribution, shifted to the right (mean, +1.57 sd). There was a significant negative correlation between pre-pregnancy HbA1c and birth weight (Spearman's R, -0.208; P = 0.016). There were no statistically significant correlations for other time points.

CONCLUSIONS

Standardized birth weight scores of the infants of diabetic mothers are higher than those of a reference population. There is no simple relationship between maternal glycaemic status and birth weight, but there appears to be a paradoxical inverse relationship between pre-pregnancy glycaemic control and standardized birth weight.

Review of unexplained infertility and obstetric outcome: a 10 year review

BACKGROUND

Increased maternal and fetal risks have been reported in pregnancies following unexplained infertility. Our aims were to examine the obstetric and perinatal outcome of singleton pregnancies in couples with unexplained infertility and explore the impact of fertility treatment.

METHODS

Women with unexplained infertility were identified from the Aberdeen Fertility Clinic Database. Their unit numbers were matched against the Aberdeen Maternity and Neonatal Databank (AMND) in order to extract obstetric records of those women with subsequent pregnancy outcomes. The general obstetric population served as a control group.

RESULTS

Women with unexplained infertility were older [30.8 versus 27.9 years, 95% confidence interval (CI) for difference = +2.4 to +3.4] and more likely to be primiparous (59 versus 40%, 95% CI = +1.3 to +1.9). After adjusting for age and parity they had a higher incidence of pre-eclampsia, abruptio placentae, preterm labour, emergency Caesarean section and induction of labour in comparison with the general population (P < 0.05). Perinatal outcome did not differ between women with unexplained infertility and those of the general population. The multiple pregnancy rate was 5.4% higher following fertility treatment than in women who conceived spontaneously (95% CI = +2.8 to +9.7).

CONCLUSIONS

Women with unexplained infertility are at higher risk of obstetric complications which persist even after adjusting for age, parity and fertility treatment. The reasons are however unclear and merit further study.

Fetal antecedents of male factor sub-fertility: how important is birthweight?

BACKGROUND

Severely reduced fetal growth has been linked to gonadal dysfunction. The aim of this study was to explore the link between birthweight and subsequent male infertility using the Aberdeen Maternity and Neonatal Databank (AMND).

METHODS AND RESULTS

Assuming 80% power at the 5% significance level, a minimum of 126 men (63 in each group) was required to show a mean difference of 0.5 (SD = 1) in the standardized birthweight scores between cases and controls. Men born locally with unexplained male factor infertility (n = 79) were identified from the infertility clinic database. Men with normal semen parameters, born in Aberdeen and attending the infertility clinic with their partners (n = 104), served as controls. The pregnancy records of these men's mothers were obtained from the AMND and a standard case-control analysis performed. In addition to standardized birthweight scores, the following variables were studied: crude birthweight, social class, maternal age, parity, obstetric history, antepartum and peripartum events.

CONCLUSIONS

No differences were found between the two groups, suggesting that low birthweight is unlikely to affect male fertility in later life.

Glucose production by the human placenta in vivo

The human placenta transports glucose by facilitated diffusion down a concentration gradient from mother to fetus. It has previously been considered incapable of glucose synthesis. However, recent work has demonstrated the presence in placental tissue of glucose-6-phosphatase, which is required for the final step in the synthesis of glucose. Following continuous intravenous infusion into the maternal circulation of the stable isotope, 6,6-(2)H(2)glucose, during elective caesarean section, we have observed isotope dilution in the umbilical vein, without further dilution in the umbilical artery. Using a mathematical model containing maternal, placental and fetal compartments, the data were compatible with the release of glucose by the placenta. We conclude that the human placenta at term can produce glucose.

Are cotinine assays of value in predicting adverse pregnancy outcome?

We investigated the utility of maternal cotinine concentration as a predictor of preterm and small-for-gestational-age (SGA) deliveries. Subjects were randomly selected from antenatal clinics, and their serum cotinine concentrations at approximately 16 weeks' gestation were compared with self-reports of smoking. The value of these measures in predicting preterm and SGA deliveries was examined, using likelihood ratios and logistic regression, for 845 women with singleton, live births. Smoking status alone (defined by self-report or cotinine) only weakly predicted preterm or SGA delivery. Self-reported moderate/high smoking (top 15% of smokers) had a likelihood ratio (LR) of 2 and a positive predictive value (PPV) of 17%. In contrast, moderate/high cotinine concentration (top 15% of smokers) had an LR of 5 and a PPV of 33%. The predictive value of cotinine was independent of associated maternal characteristics. Cotinine concentration may therefore be a useful predictor of poor pregnancy outcome, and should be considered as a screening tool.

Significant antenatal factors in the development of lumbar spinal stenosis

STUDY DESIGN

Adverse factors during pregnancy may permanently stunt the growth of the spinal canal. Subsequently, even in an optimal environment the canal cannot catch up in growth with the trunk and long bones because of its early maturation. The degree of retardation in canal size depends on the severity and timing of the adverse effect. The catch-up growth of the long bones mask the narrow canal, because the latter does not have growth potential, resulting in an adult of sufficient height and good proportions, but with a canal at risk for stenosis.

OBJECTIVES

To investigate the influence of the antenatal environment on the growth of the lumber spinal canal.

SUMMARY OF BACKGROUND DATA

To date, little is known about the effects of an adverse environment on the growth of the spinal canal, and no data have been reported on antenatal influencing factors.

METHODS

Lumbar magnetic resonance imaging scans from 58 patients were examined. Dimensions of the central spinal canals were measured by computerized image analysis and compared with the subjects' obstetric data from their mothers' pregnancies.

RESULTS

The L3 canal was found to be the most sensitive to the influence of the examined factors. Gestational age was the most significant factor; if short, it resulted in small adult canal. Small placental weight, greater maternal age, primiparity, low socioeconomic class, and low birth weight were also found to be significant in affecting the growth of the canal.

CONCLUSIONS

An adverse antenatal environment does have a permanent, retarding effect on the growth of the lumbar spinal canal.

Adjustment of birth weight standards for maternal and infant characteristics improves the prediction of outcome in the small-for-gestational-age infant

OBJECTIVE

Birth weight is a function of gestational age. Various maternal and infant characteristics also affect birth weight. This study sought to adjust for these factors to better define abnormal growth.

STUDY DESIGN

Maternal and infant characteristics from normal pregnancies were correlated with birth weight. A formula was developed and applied to a second group in which we compared perinatal outcomes in normally grown infants with those who were small for gestational age. We compared outcomes between small-for-gestational-age infants defined by the formula with those defined by conventional tables.

RESULTS

Infants defined by the formula as small-for-gestational-age were more likely to have morbidity and mortality than those who were normally grown (p < 0.001). Small-for-gestational-age infants defined by the formula had more deaths and adverse outcomes than those defined by gestational age.

CONCLUSION

Adjusting birth weight standards for maternal and infant characteristics may improve the prediction of adverse outcomes.

Pregnancy in sickle cell disease in the UK: results of a multicentre survey of the effect of prophylactic blood transfusion on maternal and fetal outcome

OBJECTIVE

To determine the outcome of pregnancies complicated by sickle cell disease in the UK during 1991-1993 and the effect of prophylactic blood transfusion programmes on maternal and fetal outcome.

DESIGN

A multicentre study.

SUBJECTS

Eighty-one pregnancies complicated by sickle cell disease and 100 pregnancies from women of black African descent without haemoglobinopathies to act as a comparative group. Pregnancies complicated by sickle cell disease were divided by the type of haemoglobinopathy and also by transfusion regimen.

MAIN OUTCOME MEASURES

Antenatal and postnatal complications of sickle cell disease, proteinuric hypertension, preterm delivery, emergency delivery by caesarean section, fetal distress, birthweight, perinatal and maternal mortality.

RESULTS

There were two maternal deaths in the 81 pregnancies and the perinatal mortality rate was 60/1000. Antenatal sickling complications occurred in 46.2% of pregnancies and postnatal sickling complications occurred in 7.7% of pregnancies. Pregnancies complicated by sickle cell disease were significantly more likely to be associated with anaemia, preterm delivery, proteinuric hypertension, birthweight below the 10th centile and caesarean section as an emergency procedure than the comparative group. Severe sickling complications occurred more commonly in the third trimester and there was some evidence that a prophylactic transfusion programme reduced the risk of this. Prophylactic transfusion did not improve obstetric outcome when compared with those pregnancies that were untransfused.

CONCLUSIONS

Sickle cell disease remains a severe complicating factor to pregnancy and perinatal mortality and maternal mortality rates in the UK have increased since last reported. A policy of exchange transfusing all women with homozygous sickle cell disease (HbSS) from 28 weeks gestation is recommended to reduce the risk of maternal complications in the third trimester and puerperium. There remains a role for earlier prophylactic blood transfusion programmes in women with poor obstetric and haematological histories.

Fertility in beta thalassaemia major: a report of 16 pregnancies, preconceptual evaluation and a review of the literature

OBJECTIVES

To examine the pregnancies, mode of delivery and outcomes, review the literature on fertility and discuss preconceptual guidance for women with beta thalassaemia major.

DESIGN

An observational study.

SUBJECTS

Sixteen women with beta thalassaemia major.

SETTING

Two collaborating London teaching hospitals.

MAIN OUTCOME MEASURES

Pre-pregnancy assessment, pregnancy course, mode of delivery, gestational age at delivery and birthweight.

RESULTS

There were 16 pregnancies in 11 women. Three of these pregnancies were terminated. Of the 13 deliveries, there were two normal deliveries, one forceps delivery and 10 caesarean sections. The main findings in a further five women seeking fertility treatment were of hypogonadotrophic hypogonadism, diabetes and cardiomyopathy.

CONCLUSIONS

Pregnancy in women with beta thalassaemia major does not appear to have a deleterious effect on the course of the disease. No increased obstetric complications were encountered except for the high caesarean section rate, essentially due to cephalopelvic disproportion. A high incidence of cardiomyopathy and diabetes dictates a careful assessment before embarking on ovulation induction to treat the hypogonadotrophic hypogonadism which is common in these women.