The vast majority of pregnancies establishing outside the womb will be in one of the fallopian tubes. The tube, even though it can swell from pressure inside it, is a very small organ compared to the womb. As the pregnancy increases in size, the tube will distend, causing pain. Bleeding into the pelvic cavity will also occur, irritating the inner surface and increasing the pain felt inside the pelvis.
The pain is normally but not necessarily localized on one side in the lower part of the abdomen. The area will also be tender to touch. If the pain at this stage has not aroused the mother's concern as to there being something amiss, the tube will go on to rupture, which usually causes quite severe acute pain, even shock.
Most ectopic pregnancies reveal themselves well before ten weeks of gestation. This is therefore a cause of pain in early pregnancy.
Can ectopic pregnancy exist without pain?
Yes, but this is quite rare. Occasionally a patient may only have symptoms of vaginal spotting in early pregnancy, without any pain. The first inkling as to the probable diagnosis is when an ultrasound scan reveals an empty uterus in the presence of pregnancy symptoms and a positive pregnancy test. Remember, an ectopic pregnancy is not always identifiable on the scan. In fact, the majority are diagnosed by exclusion.
What will cause uterine rupture and how common is this?
There has to be an inherent weakness in the uterine wall for it to rupture spontaneously. Even in labour, when the uterus is subject to stresses and strains, this remains a rare occurrence. Before labour, the main predisposing factor for this complication is a previous operation on the uterus. This could have been a caesarean section or surgery to remove fibroids.
In labour, rupture may be caused by weakening of uterine muscles as a result of multiple pregnancies (and deliveries), or over-stimulation of the uterus.
How do uterine fibroids cause pain in pregnancy?
If a woman has fibroids, pregnancy usually makes them prone to undergo some kind of degeneration, which may cause pain. The pain is usually moderate, but occasionally may be severe enough to require admission into hospital and the use of strong painkillers. It usually clears up in due course.
What causes pain in pre-eclampsia?
In severe pre-eclampsia, liver complications may cause pain on the right border of the ribcage (where the liver is situated). It may also have symptoms similar to heartburn. This is frequently a warning of impending eclampsia and, more often than not, emergency delivery will be made. Of course, there have to be other supporting features to reach this diagnosis.