Subsequent pregnancy outcomes among women with tubal ectopic pregnancy treated with methotrexate.

Lay summary: An ectopic pregnancy occurs when an embryo implants outside of the uterus, usually in a fallopian tube. When detected early, treatment is often with a medication called methotrexate. When methotrexate does not work, surgery is required. A recent clinical trial of ectopic pregnancy treatment (called GEM3) found that adding a drug called gefitinib to methotrexate did not reduce the need for surgery. We have used data from the GEM3 trial, combined with data collected 12 months after the trial finished, to investigate post-methotrexate pregnancy outcomes. We found no difference in pregnancy rates, pregnancy loss rates and recurrent ectopic pregnancy rates between those treated medically only and those who subsequently also needed surgery. The surgical technique used also did not affect pregnancy rates. This research provides reassurance that women with ectopic pregnancies treated medically who need surgery have similar post-treatment pregnancy outcomes to those treated successfully medically.

Ectopic pregnancy in animals and humans.

Ectopic pregnancy denotes a pregnancy occurring elsewhere than in the cavity of the uterus. This pathology has been recognised for years and it causes numerous maternal deaths during the first trimester of pregnancy. While this condition is well-known in humans, it is rarely diagnosed in animals. However, the causes and mechanisms leading to an ectopic implantation of the ovum are not always clearly defined in humans or animals. Two types of ectopic pregnancy are mainly recognized: (1) tubal pregnancy occurs when an oocyte is fertilized and then remains in the oviduct and (2) abdominal pregnancy occurs when the gestation develops in the peritoneal cavity. The latter may be subdivided into two subtypes: the primary form, when a fertilized oocyte enters the peritoneal cavity and becomes attached to the mesentery or abdominal viscera, and the secondary form, which follows the rupture of an oviduct or the uterus after the fetus has been implanted, and the fetus is expelled into the peritoneal cavity. Cornual, ovarian and cervical ectopic locations are less frequent. Several differences exist in ectopic pregnancies between human beings and animal species. While abdominal pregnancy has been described in both human and animal species, tubal ectopic pregnancies would appear to be restricted to primates. Other than anecdotal cases, this pathological condition does not occur in laboratory, domestic or farm animals. Several factors are described as being the cause of these differences.

Embryonic dormancy phenomenon in obstructed healthy mouse fallopian tubes.

PURPOSE: A mouse model of unilateral oviductal obstruction was designed to study whether healthy oviducts can support embryo development in an advanced stage toward blastocyst hatching and implantation when the embryos in the contralateral side normally move into the uterine cavity. METHODS: The oviducts of 80 female ICR mice (aged 5-8 weeks) were ligated unilaterally 12-40 hr postcoitus. The ligated oviducts were isolated from day 4 to 19.5 postcoitus. Embryos within the ligated oviducts were then flushed out to record the developmental stage and compared with the conceptuses in the contralateral uterine horns with unligated oviducts. Embryos recovered from ligated oviducts were then cultured in vitro to observe their potential for further development. RESULTS: In 33 mice, 53.4% (163/305) and 86.1% (241/280) of the morphologically normal blastocysts had hatched from the zona pellucida within the obstructed tube and contralateral uterine horns, respectively, on the 5th day postcoitus. The data demonstrated that the hatching process could take place within the obstructed fallopian tube, but the timing was delayed. From 5.5 to 19.5 days postcoitus, a total of 362 implanted embryos were obtained in unligated control uterine horns, but none of the 404 embryos in the artificially obstructed oviducts were implanted. The embryos within the ligated tubes were dormant in the hatched blastocyst stage as demonstrated by their ability to continue growing (98.2%) when removed from the oviduct to an in vitro environment. CONCLUSIONS: In this study, we demonstrate that mouse embryos can hatch, although delayed, in obstructed healthy oviducts. Tubal pregnancy is not likely to happen in artificially obstructed healthy mouse fallopian tubes, since all the viable embryos were dormant at the hatched blastocyst stage.

A tubal pregnancy in a rhesus monkey (Macaca mulatta).

Tubal pregnancy was diagnosed on histological section of a nodule within the uterine tube of a multiparous rhesus monkey. Clinical signs were anorexia and weight loss. The tube contained a placenta of approximately 35 days gestation, but no recognizable embryo or amnion. The ipsilateral ovary contained a degenerating corpus luteum.