Sex-specific differences in birth weight due to maternal smoking during pregnancy

Introduction We investigated the sex-specific risk of maternal smoking during pregnancy on the birth weight and the proportion of small-for-gestational-age (SGA) newborns in 888,632 (49.9%) of 1,815,318 singleton births (ca. 80% of all singleton births in Germany from 1995 to 1997) in whom data on maternal cigarette consumption were available.Results and discussion Newborns below the 10th percentile for weight and duration of pregnancy were classified SGA. Maternal smoking during pregnancy lowers the mean birth weight and increases the risk of SGA newborns. The negative effect depends on the daily number of cigarettes consumed, and is greater in girls than in boys. In non-smokers, 9.8% of the newborns were SGA, with a sex-ratio of females:males=1, but this percentage increased with increasing number of cigarettes consumed (p<0.001), as did the sex-ratio, i.e. the negative effect of smoking on growth was greater in girls than in boys. In mild smokers (1–5 cigarettes/day), the risk of giving birth to an SGA girl was 1.7275-fold (95% CI: 1.7266–1.7284) above normal, but was 1.7143-fold (95% CI: 1.7137–1.7150) in boys. More than 21 cigarettes/day increased the risk of SGA 3.15-fold for a boy, but 3.51-fold for a girl (p<0.001).Conclusion In conclusion, particularly in heavy smokers, the negative effect of maternal smoking during pregnancy on the mean birth weight and risk of SGA is significantly greater in newborn girls than in newborn boys.     

Adolescent pregnancy and perinatal outcome

Adolescent pregnancy is associated with adverse maternal and fetal effects. Potential risk factors involve early dating behavior, early initiation of smoking, alcohol and substance abuse, low academic interest, single-parent families and, above all, poverty. Girls younger than 18 years and not legally majors are psychologically and socially underdeveloped, presenting higher obstetrical risks. Maternal complications due to adolescent pregnancy include, among others: anemia; pregnancy induced hypertension; sexually transmitted diseases; and premature labor and delivery. The most common complications concerning the infant are related to: low birth weight, due either to prematurity or intrauterine growth restriction; infection; chemical dependence (due to maternal substance abuse); sudden infant death syndrome; and increased morbidity and mortality during the 1st year of age. In addition, education of teenage mothers on the importance of pre-and postnatal care can reduce the poor perinatal outcome of both mother and infant.     

Substance misuse in early pregnancy and relationship to fetal outcome

To establish the frequency of substance misuse in early pregnancy in an urban UK population, 807 consecutive positive pregnancy test urine samples were screened for a range of drugs, including cotinine as an indicator of maternal smoking habits. A positive test for cannabinoids was found in 117 (14.5%) samples. Smaller numbers of samples were positive for other drugs:- opiates (11), benzodiazepines (4), cocaine (3) and one each for amphetamines and methadone. Polydrug use was detected in nine individuals. Only two samples tested positive for ethanol. The proportion with a urine cotinine level indicative of active smoking was 34.3%. The outcome of the pregnancy was traced for 288 subjects. Cannabis use was associated with a lower gestational age at delivery (P < 0.005), an increased risk of prematurity (P < 0.02) and reduction in birth weight (P < 0.002). Whilst maternal smoking was associated with a reduction in infant birth weight (P < 0.05), this was less pronounced than the effect of other substance misuse. Conclusion This study suggests that one in six women in South London are using drugs in early pregnancy and that cannabinoid use is associated with a poorer pregnancy outcome.     

Aortic intima–media thickness in nicotine-exposed rat pups during gestation and lactation period

There have been several studies confirming an association between maternal smoking during pregnancy and low birth weight. The detrimental effect of nicotine exposure beginning in fetal life continues during lactation, in infancy and in the early childhood period. In our previous studies, we found increased aortic intima–media thickness (aIMT) as a preatherosclerotic lesion in neonates with intrauterine growth restriction and in infants of smoking mothers. We aimed to evaluate histopathologically the effect of nicotine exposure during pregnancy and lactation period on fetal growth and aIMT at postnatal 45 days of age (end of the mid-adolescent period) in rat pups living in the same conditions. Gravid rats were assigned into three groups. In nicotine A, pregnant rats received 6 mg/kg/day nicotine intraperitoneally during pregnancy from 1 to 21 days of gestation and lactation (until postnatal day 21). Nicotine B received 3 mg/kg/day nicotine for the same period. Control pregnant rats received only saline intraperitoneally. Abdominal aIMT was studied histopathologically at postnatal 45 days of age. Nicotine exposure resulted in decreased birth weight and pregnancy weight gain. The mean aIMT values of the rat pups exposed to nicotine in both nicotine A and B groups were higher than those of the control group (103.78 ± 21.33 μm, 99.11 ± 30.12 μm, and 62.56 ± 7.18 μm, respectively). In conclusion, the detrimental effect on birth weight of nicotine exposure that began in fetal life is dose dependent. Nicotine exposure during intrauterine life and the lactation period causes increased aIMT in rat pups.     

Substance use in pregnancy: do we care?

Two cohorts of substance-using women were compared retrospectively. From 1969 to 1979 a very high perinatal mortality rate (PMR 9.8%) was found among 92 polydrug-using women (1 twin excluded). Preterm delivery occurred in 25% of all pregnancies and in 30% of the children birth weight was below the 10th percentile. Nineteen women using heroin only had a worse fetal outcome (PMR 32%, preterm delivery in 47%, birth weight < 10th percentile in 42%). These results led to a strict surveillance system. In the period 1980–1989, 240 women (4 twins excluded) delivered after 16 weeks. Total fetal loss decreased to 2.1% and PMR to 0.4%, which was similar to results in controls. However, 22% of the women still delivered before 37 weeks and 27% delivered a child < 10th percentile. Methadone-using women were able to halve their dosage during pregnancy and 16 were detoxified. Multivariate analysis within the substance users of the second cohort showed that the neonatal abstinence syndrome, but not the (registered) amount of opiates used, was related to a lower birth weight. Not coping with prenatal care was related to a shorter pregnancy length. Multivariate analysis, including the controls, showed a significant relation of birth weight (345 g lower) with substance use. Also, head circumference was 0.8 cm smaller. Length of pregnancy however was related to smoking. This study shows that it is difficult to make substance users attend prenatal care, but also that women coping with prenatal care reduce substance intake. Opiate use might be responsible for lower birth weight, although not in a clear dose–response relationship, whereas lifestyle, as represented by not coping with prenatal care and the quantity of cigarette smoking, shortens the length of pregnancy.     

Gestational weight gain and pregnancy outcomes: Findings from North Indian pregnancy cohort

Despite the high prevalence of inadequate gestational weight gain (GWG) and adverse pregnancy outcomes, very few studies have addressed the association between GWG and pregnancy outcomes in South Asia. Our objectives were to estimate the prevalence of GWG during the second and third trimesters within, below and above the Institute of Medicine (IOM) guidelines, and to estimate the effect of the rate and adequacy of GWG on gestational age at the time of delivery, weight, length, length-for-age z-score (LAZ), weight-for-length z-score (WLZ) and adverse pregnancy outcomes, namely prematurity, small-for-gestational age (SGA), low birth weight (LBW), stunting and wasting at birth. We analysed data from the intervention group of the Women and Infants Integrated Interventions for Growth Study (WINGS), which is an ongoing individually randomized factorial design study. Of the 1332 women analysed, 40.2% [95% confidence interval (CI) 37.5 to 42.8] had GWG below the IOM guidelines. For every 100-g/week increase in GWG, birth weight increased by 61 g, birth length by 0.16 cm, LAZ score by 0.08 SD, WLZ score by 0.14 SD, and gestational age at birth by 0.48 days. Women with GWG below the IOM guidelines had a higher relative risk of adverse pregnancy outcomes (44% for LBW, 27% for SGA, 32% for stunting and 42% for wasting at birth) than women who had GWG within the IOM guidelines, except for prematurity. The association between GWG and LAZ scores at birth was modified by early pregnancy body mass index (BMI). GWG is a strong predictor of newborn anthropometric outcomes and duration of gestation but not prematurity.     

Maternal cigarette smoking during pregnancy, low birth weight and subsequent blood pressure in early childhood

Given the widely acknowledged inverse relationship between birth weight and blood pressure, a raised blood pressure in the offspring of smoking mothers as compared to those whose mothers did not smoke, would be anticipated by virtue of the reduction in birth weight associated with smoking during pregnancy. The objective of the present study was to test the hypothesis that maternal cigarette smoking during pregnancy has an effect on blood pressure in childhood independent of its effect on birth weight. Data was obtained from a prospective cohort study of 1708 pregnant women and their singleton offspring, delivered live at term, in Perth, Western Australia, commenced at 16 weeks gestation with serial blood pressure measurements through early childhood. Statistically significant associations were found between maternal smoking during pregnancy and systolic blood pressure at age six, between birth weight and systolic blood pressure at ages three and six, and between maternal smoking during pregnancy and birth weight. The relationship between birth weight and blood pressure in early childhood differed significantly on the basis of maternal cigarette smoking or not during pregnancy. This differential relationship persisted after adjustment for the child's current weight and socio-economic status. We concluded that intra-uterine exposure to maternal cigarette smoking increased children's blood pressure at age one through to age six. This was not wholly attributable to an effect on birth weight or confounding of the association between birth weight and subsequent blood pressure by the child's current weight or socio-economic factors. Furthermore, maternal smoking during pregnancy does not account for the acknowledged elevation in blood pressure associated with low birth weight. The present study is an exploration of a possible causal pathway underlying the birth weight/blood pressure association rather than simply a confirmation of such an association which has been detailed in many other papers.     

Maternal smoking and fetal growth of full term infants

Results of investigation into the effects of maternal smoking and other selected independent variables on fetal growth indicated that smoking by gravida was assoicated with reductions in birth weights and crown-heel lengths, but not with ponderal indices of newborn infants. Mothers of single infants were interviewed following delivery and before discharge about the amount of smoking during pregnancy. Infants were weighed and measured at birth, and step-wise multiple regression analyses were used to interpret the data for 4 groups of infants: males born to primiparas, males born to multiparas, females born to primiparas, and females born to multiparas. Results indicate that maternal smoking during pregnancy was associated with reductions in birth weights and crown-heel lengths, but not in ponderal indices of these groups of full-term infants. The effects of smoking on fetal growth did not appear to be related to poor maternal nutrition, and mean weight gains during the last 2 trimesters of pregnancy were not significantly different in smoking and nonsmoking mothers. Conflicting opinions exist concerning whether the reduction in crown-heel lengths are transitory or not; thus further study is recommended.     

Leukemia, non-Hodgkin's lymphoma, and Wilms tumor in childhood: the role of birth weight

There is emerging evidence that higher birth weight is associated with increased risk of cancer, in particular childhood leukemia. The purpose of this paper is to study whether this correlation is also significant with other childhood cancer. For this, we conducted a case–control study including 410 childhood cancer patients and 1,575 matched controls to investigate birth weight as a risk factor for leukemia, Wilms tumor, and non-Hodgkin's lymphoma. The estimated risk for all cancers has been found to be statistically and significantly higher in birth weight of more than 4,000 g (odds ratio, 2.50 and 95% confidence intervals (CI), 1.72–3.63). For leukemia, the estimated risk was 1.86 (95% CI, 1.04–3.30), for non-Hodgkin lymphoma, 1.99 (95% CI, 1.08–3.69), and being more remarkable for Wilms tumor, 4.76 (95% CI, 2.73–8.28). Moreover, moderate increased risk of both leukemia and non-Hodgkin lymphoma was also associated with birth weight between 3,000 and 3,999 g. High birth weight was associated with all cancers also when adjusted by gestational age, length at birth, and gender (odds ratio, 6.10 and 95% CI, 1.15–32.57). No associations were found for maternal alcohol consumption during pregnancy, maternal smoking, or smoking by other people at home or presence of obstetric variables (e.g., gestational diabetes, preeclampsia, and abruptio placentae). The present study supports the hypothesis that high birth weight is an independent risk factor for childhood Wilms tumor, leukemia, and non-Hodgkin lymphoma. Further studies should explore biological reasons to explain this relationship and, ultimately, to expand our knowledge about prenatal influences on the occurrence of this disease.     

Effects of smoking in pregnancy on neonatal lung function.

AIMS: To assess the effects of smoking during pregnancy on lung mechanics and lung volumes in the immediate neonatal period, before infants are exposed to passive smoking. METHODS: Lung function tests were carried out within 72 hours of delivery in infants born to 100 non-smoking and 189 smoking mothers. Lung growth was assessed by plethysmography and lung mechanics using the single breath occlusion technique and oesophageal balloon/pneumotachography. Antenatal maternal serum cotinine values were obtained from 133 mothers. RESULTS: Smoking was associated with a significant reduction in birthweight (mean 256 g, 95% CI 0.164 to 0.392), and length (mean 1.26 cm, 95% CI 0.48 to 2.00). Lung volume was not reduced when related to weight. Smoking was associated with a highly significant reduction in static compliance (Crs). This effect remained significant after relating Crs to weight and lung volume. Regression analyses showed that the Crs association was limited to the boys. Smoking was associated with a small but significant reduction in respiratory system conductance (Grs) (single breath occlusion technique) and total pulmonary conductance (Gp). These associations were limited to girls. CONCLUSIONS: Smoking in pregnancy reduces static compliance in boys and conductance in girls. There was no evidence that maternal smoking adversely affected fetal lung growth.     

Outcome of teenage pregnancy

Objective The objective of the study was to evaluate the obstetric, fetal and neonatal outcomes of teenage pregnancy in a tertiary care teaching hospital. Methods A retrospective case control study was performed over a period of 5 years. Data were retrieved from hospital records. All teenage mothers (aged 13–19 completed years at delivery) delivering in the University Hospital were taken as cases. Next 3 consecutive deliveries in the age group of 20–30 year were selected as controls for each case. For statistical analysis the cases were further subdivided into 2 groups, ≤17 years (Group A) and 18–19 years (Group B). Groups were compared for obstetric complications and neonatal outcome. Statistical analysis was done by software package SPSS 10. Results The incidence of teenage deliveries in hospital over last 5 years was 4.1%. Majority of the teenagers were primigravida (83.2% vs. 41.4%, p<0.01). Complications like pregnancy induced hypertension (PIH) (11.4% vs 2.2%, p<0.01), pre-eclamptic toxemia (PET) (4.3% vs 0.6%, p<0.01) eclampsia (4.9% vs 0.6%, p<0.01) and premature onset of labor (26.1% vs 14.6%, p<0.01) occurred more commonly in teenagers compared to controls. Teenage mothers also had increased incidence of low birth weight (LBW) (50.4% vs 32.3%, p<0.01), premature delivery (51.8% vs 17.5%, p<0.01) and neonatal morbidities like perinatal asphyxia (11.7% vs 1.9%, p<0.01), jaundice (5.7% vs 1.2%, p<0.01) and respiratory distress syndrome (1.9% vs 0.3%, p<0.05). Teenage pregnancy was also associated with higher fetal (1.9% vs 0.3%, p<0.05) and neonatal mortality (3.8% vs 0.5%, p<0.05). Conclusion Teenage pregnancy was associated with a significantly higher risk of PIH, PET, eclampsia, premature onset of labor, fetal deaths and premature delivery. Increased neonatal morbidity and mortality were also seen in babies delivered to teenage mothers. Younger teenager group (≤17 years) was most vulnerable to adverse obstetric and neonatal outcomes.     

The impact of maternal smoking on fetal and infant growth

BACKGROUND: Low birth weight is associated with accelerated postnatal growth and adverse adult health outcomes. Maternal smoking is a major risk factor for low birth weight. This study aims to assess: Pre- and postnatal growth associated with maternal smoking compared to other risk factors for low birth weight. The effect of reduction of maternal smoking on growth. SUBJECTS: A cohort (n=269) followed with ultrasound measurements in the third trimester and postnatal anthropometric measurements until 6 months of age. Mothers were interviewed about their smoking habits at 18 and 28 weeks of pregnancy. RESULTS: Maternal smoking was associated with a greater reduction in birth length SDS than other causes of equally reduced birth weight (mean difference: -0.25 SDS, P=0.013). The adjustment of gestational age, based on bi-parietal diameter at an early dating scan, indicated that mothers who reduced smoking carried smaller fetuses than mothers who continued to smoke heavily (mean difference=2.6 days, P=0.012). Birth weights in these two groups were similar (P=0.87). However at 3 months of age, reduced smoking was associated with lower weight (mean difference=-0.38 SDS, P=0.045). CONCLUSIONS: Maternal smoking was associated with a reduction of linear growth, which was more marked than that of other risk factors, and which seemed to occur before the 3rd trimester. The results indicated a beneficial effect of reduction of smoking upon third trimester growth, and that the decision to reduce smoking in mid-pregnancy may be influenced by early fetal size.     

Periodontal disease in pregnancy and low birth weight

OBJECTIVE: Recently, it has been suggested that periodontal disease during pregnancy could have a causal relationship with low weight at birth. Our objective was to evaluate the influence of periodontal disease during pregnancy on the birth weight of newborn infants. METHODS: Mothers who gave birth to low-birth-weight infants were randomly selected (Group 1 - G1; n=13). Immediately after inclusion of each mother in group 1, the mother of the next term newborn with birth weight of > 2,500 g (Group 2 - G2; n=13) was included as control. Mothers were examined by a periodontist who was not informed of the group the child belonged to. A probe was used to measure attachment loss of the alveolar bone. The extension index (EI) and severity index (SI) of the periodontal disease were determined. RESULTS: Both groups of mothers were similar in terms of maternal age, parity, color of skin, height, nutrition, smoking, drinking, socioeconomic status, prenatal examinations, premature rupture of membranes, chorioamnionitis, bacteriuria, placenta previa, abruptio placentae, previous hypertensive disease, preeclampsia, and heart disease. The characteristics of the newborns were: birth weight - G1 = 1,804 -/+ 675 g x G2 = 3,030 -/+ 516 g; gestational age - G1 = 33 -/+ 5 weeks x G2 = 39 -/+ 2 weeks; length of stay in the neonatal intensive care unit (NICU) - G1 = 128 days x G2 = 0 days. Average EI: G1 = 89.788 -/+ 18.355 x G2 = 72.420 -/+ 20.717; p=0.033. Average SI: G1 = 1.377 -/+ 0.626 x G2 = 0.754 -/+ 0.413 (OR=18.3; CI95%: 2.5-133.3; p = 0.006). After adjustment for risk factors for low birth weight, such as smoking, maternal height, bacteriuria, and previous hypertension, the odds ratio for SI dropped to 7.2 (CI95% = 0.4-125.4; P = 0.176). CONCLUSION: The multivariate analysis indicated a marked association between periodontal disease measured by SI score and low birth weight. Our data suggested that periodontal disease during pregnancy may be a risk factor for low weight at birth.     

Neonatal thrombocytopenia associated with maternal pregnancy induced hypertension

Objective  To evaluate the prevalence of thrombocytopenia in neonates born to mothers with pregnancy induced hypertension (PIH) and identify the associated material and neonatal characteristics. Methods  In the current, prospective study, platelet counts were assessed serially. Maternal and neonatal characteristic were recorded in pre-designed proforma. Primary outcome measures were thrombocytopenia defined as platelet count of <150000/mm³ and severe thrombocytopenia if counts were <30000/mm³ or <50000/mm³ with bleeding. Results  Of 97 neonates born to PIH mothers 35 (36.1%) had thrombocytopenia. In 20 (20.6%) thrombocytopenia was severe. Higher percentage of thrombocytopenia was associated with male gender (47.7%), low birth weight (71.4%) and prematurity (67.4%). Severe thrombocytopenia was significantly associated with low birth weight (OR: 4.58; 95% CI: 0.98–21.3; p<0.03) and prematurity (OR: 2.52; 95% CI: 0.87–7.24; p<0.05). Material parity, onset of PIH, and medications did not seem to be associated significantly. Conclusion  Premature and low birth weight neonates born to mothers with pregnancy induced hypertension would require scrutiny for thrombocytopenia during early neonatal period.     

Management of infants with intra-uterine growth restriction

Intra-uterine growth restriction (IUGR) and prematurity are the two causes for delivery of low birth weight infants. In India, IUGR contributes to almost two-thirds of infants in this category. Poor nutritional status and frequent pregnancies are common pre-disposing conditions in addition to obstetric and medical problems during pregnancy. Growth restriction may be symmetrical or asymmetrical depending on the time of insult during pregnancy. The pathological insult in an asymmetrical IUGR occurs during the later part of the pregnancy and has a brain-sparing effect. Common morbidities are more frequent in <3rd percentile group as compared to 3rd–10th percentile group. Guidelines for management of IUGR neonates in these two groups have provided in the protocols.     

Low maternal education is associated with increased growth velocity in the first year of life and in early childhood: the ABCD study

The objective of this study is first to examine the relation of maternal education and growth velocity during the first year of life and early childhood (1–5 years). The second objective is to determine the potential explanatory role of standardized birth weight, maternal smoking during pregnancy, maternal prepregnancy body mass index (BMI), and infant feeding practice in this relation. We used longitudinal growth data of 1,684 participants with Dutch ethnicity participating in a population-based cohort study (Amsterdam Born Children and their Development study). Growth velocity of weight and of weight-for-length were calculated by subtracting the weight and weight-for-length standard deviation scores (SDS), respectively of two time periods. In the first year of life, children with low-educated mothers had an increase in SDS of 0.26 (95 % confidence interval (CI) 0.08–0.45) for weight compared to children with high-educated mothers. In early childhood, children with low-educated mothers had a 0.27 SDS (95 % CI 0.11–0.42) increase for weight-for-length, compared to children with high-educated mothers. Using path analysis, these inequalities could partly be explained by maternal smoking, duration of breastfeeding, maternal age, and maternal BMI. Conclusion: Children with low-educated mothers had an increased weight gain during the first year of life and an increased weight-for-length gain in early childhood compared to children with high-educated mothers. Although underlying mechanisms were not completely clarified, an optimal duration of breastfeeding, cessation of maternal smoking, and reduction of maternal BMI seem to reduce these educational inequalities in early growth and possible adverse consequences of accelerated growth.     

Perinatal outcome in an obstetric cohort of Mozambican women

A prospective cohort of 908 consecutively enrolled pregnant women with biparietal diameter (DBP) compatible with gestational age equal to or below 21 weeks were followed up regularly at 2-4 weeks intervals. Normal antenatal care routine was applied. The newborns were followed until 7 days postpartum. The setting was two suburban antenatal clinics in Maputo and the delivery ward at the Maputo Central Hospital. The main outcome variables were low birth weight (LBW), preterm delivery, intrauterine fetal death, perinatal death and small for gestational age (SGA). For each of these variables the odds ratio for maternal risk factors was estimated with 95 per cent confidence interval and multiple logistic regression analysis was used. LBW occurred in 16.2 per cent and low maternal weight, low weight gain during pregnancy and not having a living child were risk factors. Prevalence of preterm birth was 15.4 per cent and low weight gain during pregnancy and malaria in the perinatal period were risk factors. Four per cent of mothers delivered stillborns and syphilis serology (positive VDRL test) was a risk factor. Perinatal death occurred in 4.7 per cent. These deaths were associated with being SGA, LBW or preterm at birth. Of the cohort women, 9.7 per cent delivered SGA newborns. It was concluded that maternal constitutional factors, particularly maternal weight gain, maternal height and maternal weight as well as syphilis and malaria during pregnancy, need to be given attention concerning the adverse outcomes addressed. The establishment of an obstetric cohort, followed prospectively, was possible in a low-income setting with limited numbers lost to follow-up at delivery.     

Subsequent pregnancy affects nutritional status of previous child: a study from Bhutan

In a rural area of Bhutan, anthropometric measurements of 113 children and interviews with their mothers were carried out monthly for 32 months. The purpose of the study was to investigate the effect of a mother's subsequent pregnancy on growth in weight of her last–born child. The children whose mothers had a subsequent birth interval of 18–30 months were matched for date of birth with children whose mothers did not become pregnant. Growth of the children during the subsequent pregnancy was compared with growth during the same period of children whose mothers were not pregnant. A statistically significant reduction of 28% was found (p < 0.05), which was most pronounced in early pregnancy. A similar trend was found for change in mid–upper–arm circumference (p < 0.05). The study provides evidence of a causal relationship between a moderate subsequent pregnancy interval and a concurrent reduction in growth rate for the previous child     

Dietary change mediates relationships between stress during pregnancy and infant head circumference measures: the QF2011 study

Prenatal maternal stress can adversely affect birth outcomes, likely reflecting effects of maternal stress hormones on fetal development. Maternal stress might also induce behavioural changes, such as dietary change, that might influence fetal development. Few studies have documented relationships between stress and dietary change in pregnancy. We analysed stress and dietary change among 222 pregnant women exposed to the 2011 Queensland Floods. We assessed women's objective hardship, subjective distress and cognitive appraisal of the disaster; changes in their diets and their associations with infants' gestational age, weight, length and head circumference at birth, head circumference to birth length ratio (HC/BL) and ponderal index. Greater objective hardship was correlated with more negative dietary change, skipped meals and skipped multivitamins. There were no direct effects of stress or dietary change on birth outcomes. However, we observed an interactive effect of dietary change and exposure timing on head circumference for gestational age (HC for GA) (p = 0.010) and a similar trend for HC/BL (p = 0.064). HC for GA and HC/BL were larger among children whose mothers experienced negative changes to their diet in early pregnancy compared with later pregnancy, consistent with a ‘head‐sparing’ response with early gestation exposure. Further analyses indicated that dietary change mediates the relationship between objective hardship because of the floods and these outcomes. This is the first report of relationships among an independent stressor, dietary change and birth outcomes. It highlights another possible mechanism in the relationship between prenatal maternal stress and child development that could guide future research and interventions.