Doppler velocimetry in pregnancy

Pregnancy-specific stress, fetoplacental haemodynamics, and neonatal outcomes in women with small for gestational age pregnancies: a secondary analysis of the multicentre Prospective Observational Trial to Optimise Paediatric Health in Intrauterine Growth Restriction

OBJECTIVES

To examine associations between maternal pregnancy-specific stress and umbilical (UA PI) and middle cerebral artery pulsatility indices (MCA PI), cerebroplacental ratio, absent end diastolic flow (AEDF), birthweight, prematurity, neonatal intensive care unit admission and adverse obstetric outcomes in women with small for gestational age pregnancies. It was hypothesised that maternal pregnancy-specific stress would be associated with fetoplacental haemodynamics and neonatal outcomes.

DESIGN

This is a secondary analysis of data collected for a large-scale prospective observational study.

SETTING

This study was conducted in the seven major obstetric hospitals in Ireland and Northern Ireland.

PARTICIPANTS

Participants included 331 women who participated in the Prospective Observational Trial to Optimise Paediatric Health in Intrauterine Growth Restriction. Women with singleton pregnancies between 24 and 36 weeks gestation, estimated fetal weight <10th percentile and no major structural or chromosomal abnormalities were included.

PRIMARY AND SECONDARY OUTCOME MEASURES

Serial Doppler ultrasound examinations of the umbilical and middle cerebral arteries between 20 and 42 weeks gestation, Pregnancy Distress Questionnaire (PDQ) scores between 23 and 40 weeks gestation and neonatal outcomes.

RESULTS

Concerns about physical symptoms and body image at 35-40 weeks were associated with lower odds of abnormal UAPI (OR 0.826, 95% CI 0.696 to 0.979, p=0.028). PDQ score (OR 1.073, 95% CI 1.012 to 1.137, p=0.017), concerns about birth and the baby (OR 1.143, 95% CI 1.037 to 1.260, p=0.007) and concerns about physical symptoms and body image (OR 1.283, 95% CI 1.070 to 1.538, p=0.007) at 29-34 weeks were associated with higher odds of abnormal MCA PI. Concerns about birth and the baby at 29-34 weeks (OR 1.202, 95% CI 1.018 to 1.421, p=0.030) were associated with higher odds of AEDF. Concerns about physical symptoms and body image at 35-40 weeks were associated with decreased odds of neonatal intensive care unit admission (OR 0.635, 95% CI 0.435 to 0.927, p=0.019).

CONCLUSIONS

These findings suggest that fetoplacental haemodynamics may be a mechanistic link between maternal prenatal stress and fetal and neonatal well-being, but additional research is required.

Prenatal stress and hemodynamics in pregnancy: a systematic review

Maternal prenatal stress is associated with preterm birth, intrauterine growth restriction, and developmental delay. However, the impact of prenatal stress on hemodynamics during pregnancy remains unclear. This systematic review was conducted in order to assess the quality of the evidence available to date regarding the relationship between prenatal stress and maternal-fetal hemodynamics. The PubMed/Medline, EMBASE, PsycINFO, Maternity and Infant Care, Trip, Cochrane Library, and CINAHL databases were searched using the search terms pregnancy; stress; fetus; blood; Doppler; ultrasound. Studies were eligible for inclusion if prenatal stress was assessed with standardized measures, hemodynamics was measured with Doppler ultrasound, and methods were adequately described. A specifically designed data extraction form was used. The methodological quality of included studies was assessed using well-accepted quality appraisal guidelines. Of 2532 studies reviewed, 12 met the criteria for inclusion. Six reported that prenatal stress significantly affects maternal or fetal hemodynamics; six found no significant association between maternal stress and circulation. Significant relationships between prenatal stress and uterine artery resistance (RI) and pulsatility (PI) indices, umbilical artery RI, PI, and systolic/diastolic ratio, fetal middle cerebral artery PI, cerebroplacental ratio, and umbilical vein volume blood flow were found. To date, there is limited evidence that prenatal stress is associated with changes in circulation. More carefully designed studies with larger sample sizes, repeated assessments across gestation, tighter control for confounding factors, and measures of pregnancy-specific stress will clarify this relationship.

Stress and placental resistance measured by Doppler ultrasound in early and mid-pregnancy

OBJECTIVES

To examine the association between self reports and biomarkers of stress and placental resistance (measured by Doppler ultrasound of the uterine and umbilical arteries), to determine if restriction of blood flow to the placenta is a mechanism by which stress might affect health during pregnancy.

METHODS

Eight hundred and seventy-two women had ultrasound examinations of the uterine artery at 15-19 weeks' gestation and the uterine and umbilical arteries at 24-29 weeks, and resistance and pulsatility indices were calculated. Psychosocial stress was measured by telephone interview and self-administered questionnaire using several validated tools twice during the pregnancy. Cortisol and corticotropin-releasing hormone (CRH) were measured twice during the pregnancy. Linear and hierarchical models were used to examine the relationships among reported stress, stress hormones and placental Doppler indices.

RESULTS

The umbilical artery resistance index was higher in younger women, those with less education, those who were single and those who smoked. The uterine artery pulsatility index was higher in women with pre-eclampsia, those living alone, those with high body mass index, and those who gained the least weight during pregnancy. A higher CRH level was associated with small increases in uterine artery pulsatility and umbilical artery resistance indices. Psychosocial measures of stress were not consistently associated with higher placental resistance.

CONCLUSIONS

Increased CRH levels may be associated with increased placental resistance. Otherwise, these findings do not support the hypothesis that restriction of blood flow to the fetus is a major mechanism by which stress affects infant health.