Ultrasound examination of the fetus enables diagnosis of many major malformations during pregnancy, providing the possibility to consider termination of the pregnancy. As a result, in many cases the incidence of malformations at birth does not represent their true incidence.
To determine the impact of prenatal diagnosis and pregnancy termination on the relative incidence of malformations at birth among Jews and Muslim Arabs in Israel.
Methods: Data on selected major malformations in 2000–2003 were collected from the two large central databases of the Ministry of Health and the Central Bureau of Statistics which contain information regarding births, stillbirths and terminations of pregnancies.
For many malformations the total incidence was much higher than the incidence at birth. For almost all of the malformations studied, the total incidence was higher
in Muslims than in Jews and the differences were further accentuated among the liveborn because of the differences in the rate of pregnancy terminations.
Conclusions: In order to detect possible influences of environmental or genetic factors on major malformations in Israel, it is critical to look at data including pregnancy terminations, stillbirths and live births.
Zlotogora J, Haklai Z, Rotem N, Georgi M, Rubin L: The impact of prenatal diagnosis and termination of pregnancy on the relative incidence of malformations at birth among Jews and Muslim Arabs in Israel. Isr Med Assoc J; 2010 Sep;12(9):539-42
For many of the malformations studied the rate at birth did not represent even an estimate of the true incidence. The most extreme example was anencephaly. Among Jews the rate of live births with anencephaly (0.45 /10,000 live births) was 10.9
times lower than its true incidence (4.99/10,000 live births).
In the present study the differences in the rate of pregnancy termination between Jews and Muslims were evident. The differences were present both for a severe and lethal malformation such as anencephaly (82% terminated among Jews and 60% among Muslims) and less severe malformations such as spina bifida (62% and 32%) or Down syndrome (57% and 24%).
However, an important question that must be addressed but cannot be resolved by the present study is whether the differences in the rate of pregnancy termination represent only a difference in the approach to pregnancy or are also due to differences in the ability to arrive at a diagnosis during pregnancy. In the example of anencephaly, since almost all the cases are diagnosed during pregnancy, the differences in the rate of termination among the two groups are mainly explained by differences concerning the approach to termination.