Proliferation of prenatal ultrasonography

Background

The extent to which temporal increases in the use of prenatal ultrasonography reflect changes in maternal risk is unknown. In this population-based study, we examined the use of prenatal ultrasonography from 1996 to 2006 in Ontario.

Methods

With fiscal year 1996/97 as the baseline, we evaluated the relative risk (RR) and 95% confidence interval (CI) for the change in rates of ultrasonography for each subsequent year. The RR was adjusted for maternal age, income, rural residence, maternal comorbidities, receipt of genetics consultation or amniocentesis — all in the index pregnancy — and history of complications in a prior pregnancy.

Results

The study sample consisted of 1 399 389 singleton deliveries. The rate of prenatal ultrasonography increased from 2055 per 1000 pregnancies in 1996 to 3264 per 1000 in 2006 (adjusted RR 1.55, 95% CI 1.54–1.55). The rate increased among both women with low-risk pregnancies (adjusted RR 1.54, 95% CI 1.53–1.55) and those with high-risk pregnancies (adjusted RR 1.55, 95% CI 1.54–1.57). The proportion of pregnancies with at least four ultrasound examinations in the second or third trimesters rose from 6.4% in 1996 to 18.7% in 2006 (adjusted RR 2.68, 95% CI 2.61–2.74). Paradoxically, this increase was more pronounced among low-risk pregnancies (adjusted RR 2.92, 95% CI 2.83–3.01) than among high-risk pregnancies (adjusted RR 2.25, 95% CI 2.16–2.35).

Interpretation

Substantial increases in the use of prenatal ultrasonography over the past decade do not appear to reflect changes in maternal risk. Nearly one in five women now undergo four or more ultrasound examinations during the second and third trimesters. Efforts to promote more appropriate use of prenatal ultrasonography for singleton pregnancies appear warranted.The rapid proliferation of diagnostic imaging is a challenge for the containment of health care expenditures and for system sustainability in many countries.¹ The ensuing debate among clinicians, researchers and policy-makers has become increasingly contentious and highly politicized.^2,3 In Canada, the annual operational costs for diagnostic imaging now total more than $2.2 billion.⁴ Prenatal ultrasonography is one of the most rapidly proliferating imaging tests, this expansion being marked most strikingly by an increase in the proportion of women undergoing multiple pre-natal examinations for a single pregnancy.⁵ Although guidelines generally recommend that two ultrasound examinations be performed in a pregnancy without complications — one in the first trimester, for measurement of nuchal translucency to screen for aneuploidy, and one in the second trimester to screen for fetal anomalies — it is conceivable that the proliferation of prenatal ultrasonography reflects changes in maternal risk over time.^6–10In other areas of health care, interventions that are most beneficial to high-risk individuals are frequently directed to low-risk populations.^11–13 We hypothesized that increasing trends in the use of prenatal ultrasonography could not be explained solely by pregnancy risk and would be evident among low-risk pregnancies. Accordingly, we performed a population-based study to examine the annual rates of prenatal ultrasonography, adjusted for maternal risk profiles.     

Epidemiological prenatal ultrasound studies

Epidemiological studies have indicated no association between diagnostic ultrasound exposure during pregnancy and childhood malignancies. Diagnostic ultrasound imaging does not seem to influence birth weight, whereas frequent Doppler ultrasound was associated with reduced birth weight in one study. Most experts do not believe that ultrasound exposure during pregnancy is associated with reduced birth weight. There are no confirmed statistically significant associations between ultrasound and dyslexia and neurological development during childhood. However, two randomised controlled trials and two cohort studies have been unable to rule out a possible association between ultrasound and left-handedness among males.     

At the back stage of prenatal care: Japanese Ob-Gyns negotiating prenatal diagnosis

In this article, I explore the reluctance of Japanese ob-gyns to discuss prenatal diagnosis (PND) tests with pregnant women. The analysis focuses on the culturally specific ways in which ob-gyns formulate their cautiousness and criticism toward PND while invoking a local moral economy. Analyzing ob-gyns' accounts, I show how the ambiguities of PND are constituted in a specific moment in Japanese culture, history, disability politics, and national reproductive policies and are formulated through local paradigms of thinking about pregnant women, their fetuses, and the process of becoming a person in Japanese society. Finally, I show how PND in Japan is pushed to a "back-stage" realm in which the diagnosis for fetal anomalies is practiced in secrecy.     

Relationship of prenatal alcohol use with maternal and prenatal factors in American Indian women

Demographic factors and patterns of substance use among women who did not consume alcohol during pregnancy were compared to women who did consume alcohol during pregnancy. One-hundred seventy-seven Northern Plains Indian women who received prenatal care at an urban clinic in a rural state were screened for substance use as part of the validation study with a self-administered questionnaire. Women who drank during pregnancy were more likely to be single and have less education than women who did not drink. While most of the women in the study had available transportation resources, the women who drank during pregnancy were less likely to have transportation than the women who did not drink. Women who drank during pregnancy consumed more alcohol more frequently before pregnancy than did women who drank before but not during pregnancy. Compared to women who did not drink during pregnancy, women who drank during pregnancy were more likely to smoke cigarettes and use illicit drugs, to have parents who drank, to feel they drank the same or more than other pregnant women, or to have experienced more relationship breakups and physical and emotional abuse. Prenatal patients who drink alcohol during pregnancy need more intensive counseling regarding their multiple risk behaviors.     

Puberty after prenatal growth restraint

There is increasing evidence for a link between prenatal growth and pubertal development. Here we highlight a selection of pubertal characteristics in children who were born small for gestational age (SGA). Boys born SGA are at risk of high levels of follicle-stimulating hormone (FSH) and low levels of inhibin B and a small testicular volume during adolescence. In girls born SGA, the age at pubertal onset and the age at menarche are advanced by about 5-10 months; prenatal growth restraint may also be associated with higher FSH levels and smaller internal genitalia in adolescence. The ovulation rate was found to be reduced in adolescent girls born SGA, and an insulin-sensitizing therapy was capable of raising this low ovulation rate. Menarche is definitely advanced in girls born SGA with precocious pubarche and in those with an early-normal onset of puberty. Current evidence suggests that insulin resistance is a key mechanism linking a post-SGA state to early menarche; hence, insulin sensitization may become a valid approach to prevent early menarche and early growth arrest in girls born SGA.