Selective Termination of Pregnancy: About a Case of Anencephaly on a Bi-Chorial Twin Pregnancy

Background: The discovery of a lethal or disabling malformation requires a thoughtful decision in the event of a termination of pregnancy on medical grounds. The termination of pregnancy can be selective in the case of multiple pregnancies if a twin is suffering from a serious condition. Objective: To report a case of anencephaly on a twin pregnancy and conduct a review of literature. Case: This is a 30-year-old woman carrying a pregnancy obtained after the third attempt at in vitro fertilization (IVF) with transfer of two embryos. No risk factor was found on this pregnancy except for the twinning. The diagnosis was made at 14 weeks +1 day during first term ultrasound, which discovered an on-going bi-chorial bi-amniotic twin pregnancy, with twin B (TB) carrying a defect on his head. A selective interruption was performed on TB at 16 weeks by cordonal injection with potassium chloride. The pregnancy went on without incident and with spontaneous vaginal delivery of the second twin at 39 weeks of pregnancy. Despite the selective termination, the pregnancy went on without any complication. Conclusion: Anencephaly on twin pregnancy is a rare occurrence. In a bichorial pregnancy, a selective feticide can improve the gestational age at birth.


Introduction
Ultrasound remains virtually the only tool for detecting fetal malformations.
Several malformations may be found, including abnormalities in the cranial vault. The severity of malformations varies. The discovery of a lethal or disabling malformation requires preparation of the parents to a difficult psychological situation, and a thoughtful decision in the event of a termination of pregnancy on medical grounds.
The termination of pregnancy can be selective in the case of multiple pregnancies if a twin is suffering from a serious condition. Thus, a selective feticide is envisioned after antenatal diagnosis of a severe chromosomal or morphological anomaly incompatible with extra-uterine life. In the case of a twin pregnancy, the problem is that of the survival of the second twin and the evolution of the pregnancy after the feticide.

Objectives
Reporting a case of selective pregnancy termination (SPT) for anencephaly on twin pregnancy, outlining the prognosis of the second twin and reviewing the literature.

Method
We have studied a case of a bichorial bi amniotic twin pregnancy obtained by medically assisted procreation. During the first term ultrasound a twin was diagnosed with anencephaly and the other without abnormality. We participated in a multidisciplinary meeting during which the decision of pregnancy termination was taken. The case was collected at the Arpajon hospital in France. We undertook a literature review.
Ethical Concern: We obtained verbal agreement from the patient for publication. Anonymity was guaranteed.

Observation
Our patient was a 30-year-old pregnant woman, of French origin. In her history we noted a secondary infertility of male origin, namely oligoasthenoteratospermia. Her obstetrical record noted two pregnancies and one delivery which led to a child in good health.
Her second pregnancy was obtained after the third attempt at implantation during a medically-assisted in vitro fertilization (IVF). Two embryos were trans-  (Table   1). Faced with this, the patient is referred for better management.

Comments and Literature Review
Anencephaly is a  or total absence of the brain, skull and scalp. It affects 1.4 to 4.7 per 1000 births [1]. It is sometimes associated with spina bifida or omphalocele [2] and may take part in a polymalformative syndrome [3]. The causes of anencephaly remain unknown. The Congolese and Moroccan studies respectively incriminate consumption of potatoes infested with Phytophthora infestans and of Fenugreek in periconceptional period [4] [5] [6]. An epidemiological study [2] incriminates maternal hyperthermia, insufficiency or excess of certain nutrients, chronic diseases, and certain chemical agents. In our case, none of these factors were found to explain the occurrence of anencephaly. Antenatal diagnosis of anencephaly is possible as from the first term. The ultrasound image is that of an exencephaly, the precursor of anencephaly, characterized by the absence of cranial vault and dura mater, while cerebral tissue floats in the amniotic fluid [7]. This demonstrates the value of first term ultrasound for monitoring pregnancy. In our study, the diagnosis was made at 14 Weeks +1 day whereas several African studies indicate a late first ultrasound. In particular Amadou et al. [8], in Togo about a series of six cases of anencephaly on twin pregnancies, indicate a diagnosis made during second or third terms. The anencephalic twin can be a part of a monochorial or a bichorial twin pregnancy [9] [10]. This knowledge is essential to the treatment as it conditions the technique used for the interruption. Bichorial and monochorial twin pregnancies must be treated differently. The major risks associated with anencephaly on twin pregnancies are hydramnios and premature delivery.
In an English series carried out on 2329 twin pregnancies from 1998 to 2002, the rate of hydramnios was 36% [11]. Another series [12] reports 57% of hydramnios in bichorial twin pregnancies; we can therefore say that the selective feticide in our study allowed the pregnancy to proceed normally avoiding hydramnios, and reducing the risk of premature delivery [10] [13] [14].
In developing countries, on the other hand, selective feticide is not always feasible, exposing the pregnancy to hydramnios with its risks including rupture of membranes and premature delivery. It should be noted, however, that this complication may be counterbalanced in cases of mono-amniotic pregnancy by the swallowing of amniotic fluid by the normal foetus [15].
Apart from these two main risks, there was 7.9% risk of miscarriage and 12.4% risk of premature delivery between 25 and 32 weeks in Evans et al.'s study [16].

C. T. Aguemon et al. Open Journal of Obstetrics and Gynecology
Due to the risk of prematurity, it may be wise to wait 32 to 34 weeks to conduct the selective interruption [17]. In Evans' series [16], 16

Conclusion
Anencephaly on twin pregnancy is rare. Ultrasound allows early diagnosis and treatment, in order to reduce the mortality of the normal twin. In bi-chorial pregnancies, a selective feticide can increase gestational age at birth. The risks of this act are miscarriage and premature birth which must be taken into account and discussed with the couple.