The reasons for termination of pregnancy in the third trimester

Br J Obstet Gynaecol. 1999 Apr;106(4):297-303. doi: 10.1111/j.1471-0528.1999.tb08265.x.


Objective: To analyse the process in making decisions leading to termination of pregnancy in the third trimester and to evaluate the maternal morbidity associated with this procedure.

Design: Retrospective study.

Setting: The Maternité Port Royal University Hospital, Paris, France.

Population: A consecutive series of 956 terminations of pregnancy performed for fetal anomalies in singleton pregnancies, 305 of which were in the third trimester and 651 in the second.

Main outcome measures: Indications for termination of pregnancy; process leading to late termination of pregnancy; maternal morbidity.

Results: One hundred and thirteen (37%) third trimester terminations of pregnancy were associated with false negative resulted from the results of earlier screening tests. In 15 terminations (5%), the decision was postponed, although the poor fetal prognosis was established earlier. In 55 (18%) the diagnosis was not possible earlier than the third trimester, and in 122 (40%) the diagnosis was possible earlier but the poor prognosis for the fetus was not established until the third trimester. Maternal morbidity due to termination of pregnancy was similar in the second and third trimester.

Conclusion: One-third of late terminations of pregnancy could have been avoided by more efficient screening in the second trimester. However, because fetal prognosis is not always clear when a malformation is diagnosed, postponing the decision until fetal development allows more thorough evaluation and may avoid unnecessary termination of pregnancy in the second trimester. This could be the main beneficial aspect of not setting a limit to the gestational age for performing termination of pregnancy.

PIP: The processes associated with late terminations of pregnancies with a fetal abnormality were assessed in a retrospective study of 956 consecutive second- and third-trimester abortions performed at the Maternite Port Royal University Hospital in Paris, France, in 1986-94. 651 of these terminations were performed in the second trimester and 305 in the third trimester. The main indications for third-trimester abortion were neurologic anomalies, multiple malformations with a normal karyotype, and chromosomal anomalies diagnosed after an abnormal routine ultrasound scan. In 55 cases (18%) of third-trimester induced abortion, the anomaly could not have been diagnosed before the third-trimester. This group included cases of autoimmune hydrops occurring in the third trimester, Down's syndrome revealed by sonographic anomalies, and structural chromosomal anomalies revealed by intrauterine growth restriction or caused by cytomegalovirus infection. In an additional 122 (40%) of the third-trimester abortions, the prognosis of the anomaly could not have been established firmly until the third trimester, even though prenatal diagnosis was feasible earlier. The majority of these cases involved cerebral ventriculomegalies. In another 15 cases (5%), the poor prognosis of the fetus was established in the second trimester, but the termination was postponed, either by the physician or because the couple required more time to reach a decision. In the final 113 cases (37%), the condition for which pregnancy termination was performed in the third trimester could have been identified earlier in pregnancy, but screenings during the second trimester resulted in false-negative findings. Myelomeningocele, trisomy 18 and 13, and lethal dwarfism accounted for the majority of these potentially avoidable third-trimester terminations.

MeSH terms

  • Abortion, Induced* / adverse effects
  • Abortion, Induced* / methods
  • Chromosome Aberrations*
  • Chromosome Disorders*
  • False Negative Reactions
  • Female
  • Humans
  • Pregnancy
  • Pregnancy Trimester, Third
  • Prenatal Diagnosis
  • Prognosis
  • Retrospective Studies