Why is ectopic pregnancy dangerous?
An ectopic (outside) pregnancy occurs when the sperm (male gamete) fertilizes the ova (female gamete) and the formed zygote implants at sites other than inside the uterine cavity. Extra-uterine sites where the zygote can get implanted are the fallopian tubes, ovaries, cervix and other sites in the abdomen.
Causes of ectopic pregnancy are a previous history of ectopic history, age more than 35 years, congenital (birth) defects in fallopian tubes or previously operated fallopian tubes. Confirmation of ectopic pregnancy can be done by ultra sonography and high beta-Hcg levels.
Implantation is a very important stage post-fertilization as the site where the zygote implants will have the future placenta and also, the embryo. In a normal pregnancy, the zygote implants within the cavity of the womb (uterus). The commonest site of implantation in case of an ectopic pregnancy is one of the fallopian tubes as the ova travels from the ovary to the uterine cavity through these tubes. This is also called as a tubal pregnancy. The risk of pregnancy in the tubes is very high as they are hollow, very narrow and highly distensible. Initially, the zygote grows slowly but to have a full grown fetus in the fallopian tubes is impossible. Only the uterine cavity is capable of accommodating the fetus due to its highly distensible and thick muscular walls. Not only does the fetus grow but adjacent to it is the placenta. The growing zygote invades the cellular lining as well as the blood vessels of the fallopian tubes eventually ending in a rupture of the tube wall as there is hardly any room to accommodate a tiny zygote and placenta in such a narrow structure. To begin with, the first symptom will be a severe lower abdominal pain along with vaginal bleeding and a positive pregnancy test. Ectopic pregnancies have high levels of beta- Hcg (human chorionic gonadotrophin) levels which give rise to severe morning sickness (nausea of pregnancy). Profuse internal hemorrhage (bleeding) is the most imminent consequence of a ruptured tube and is potentially fatal.
If the zygote gets implanted anywhere in the abdomen like the intestines etc, then the placenta gets positioned on the nearby organs. Removal of placenta in such cases causes massive internal bleeding as it is adherent to the organ on which it grows.
An ectopic pregnancy can never continue to birth, it needs to be terminated or else it will rupture. It is a life threatening condition for the mother. It is necessary to diagnose the case early and then terminate the pregnancy or risk mother and child’s life. The second situation is much more fatal than the first. On early diagnosis, the pregnancy can be medically or surgically terminated. If the ectopic pregnancy ruptures the patient will feel a sudden, bursting pain in the lower abdomen. This pressure-like feeling is due to the sudden and intense internal bleeding. Hemorrhage is to such an extent that the patient may bleed to death if transfusion is not done immediately. There might be fainting and giddiness due to a sudden drop in blood pressure.
The remnants of the fetal tissue should be removed completely post-rupture as it might re-grow in rare cases or may cause get infected.
Summary: You should see a doctor if you have lower abdomen pain and vaginal spotting (bleeding) along with absence of periods as it may be an ectopic pregnancy. Hence, every ectopic pregnancy is risky and is considered as a surgical emergency.