Causes of ectopic preganancy (Tubal pregnancy)

An ectopic pregnancy is one in which the fertilized ovum is implanted and develops outside the normal uterine cavity. Ectopic pregnancy still contributes significantly to the cause of maternal mortality and morbidity.

Causes :-

- Factors preventing or delaying the migration of the fertilized ovum to the uterine cavity.
- Factors facilitating nidation of the fertilized ovum in the tubal mucosa.

1. Factors preventing or delaying migration -

• Pelvic inflammatory disease (PID) increases the risk of ectopic pregnancy.
• Selected contraception failure.
• Use of intrauterine device.
• Tubal surgery increase the risk of tubal pregnancy.
• Intrapelvic adhesion following pelvic surgery.
• Prior induced abortion significantly increases the risk.

2. Factors facilitating nidation in the tube -

• Early resumption of the trophoblastic activity is probably due to premature degeneration of the zona pellucida.
• Increased decidual reaction.
• Tubal endometriosis.

What is bearing down efforts during labour

It is the additional voluntary expulsive efforts that appear during the second stage of labour (expulsive stage). It is initiated by nerve reflex set up due to stretching of the vagina by the presenting part. In majority, this expulsive effort start spontaneously with full dilatation of the
cervix. It helps in passing the baby through birth canal.
                    Along with the uterine contraction, the woman is instructed to exert downward pressure as done during straining at stool. Sustained pushing beyond the uterine contraction is discouraged. In the first stage of labour, bearing down efforts may suggest uterine dysfunction. There may be slowing of the fetal heart rate during pushing and it should come back to normal once the contraction is over.

Pain during labour

The first symptom to appear is intermittent painful uterine contractions followed by expulsion of blood stained mucus (show) per vaginam. Only few drops of blood mixed with mucus is expelled and any excess should be considered abnormal.
                               The pains are felt more anteriorly with simultaneous hardening of the uterus which is bodily pushed forwards. Initially, the pains are not strong enough to cause discomfort and come at varying intervals of 15-30 minutes with duration of about 30 sec. But gradually the interval becomes shortened with increasing intensity and duration so that in late first stage the contraction comes at intervals of 3-5 minutes and lasts for about 45 sec. The relation of pain with uterine contraction is of great clinical significance.
                                In normal labour, pains are usually felt shortly after the uterine contractions begin and pass off before complete relaxation of the uterus. Clinically, the pains are said to be good if they come at intervals of 3-5 minutes.

Role of gravity after childbirth

After the childbirth gravity play important role. Soon after the delivery of the baby, it should be placed on a tray covered with clean dry linen with the head slightly downwards (about 15 degree downward).

• It facilitates drainage of the mucus accumulated in the trachco-bronchial tree by gravity. 
• The tray is placed between the legs of the mother and should be at a lower level than the uterus to facilitate gravitation of blood from the placenta to the infant.

How the baby's head comes out during labour

The body of uterus, cervix and vagina together form an uniformly curved canal called the birth canal. Normally, at the onset of labour with the head non-engaged, the pelvic structures anterior to the vagina are urethra and bladder and those posterior to the vagina are the pouch of Douglas with coils of intestine, rectum anal canal and perineum.
                                    As the head descends down with progressive dilatation of the vagina, it displaces the anterior structures, upwards and forwards and the posterior structures downwards and backwards, as if the head is passing through a swing door. The bladder which remains a pelvic organ throughout the first stage becomes an abdominal organ in the second stage of labour. There is no stretching of the urethra. The urethra is pushed anteriorly, with the neck of the bladder still lying in the vulnerable position behind the symphysis pubis. The changes in the posterior structures due to downward and backward displacement are marked when the head is sufficiently low down and in the stage of 'crowing'. The perineum which is a triangular area of about 4 cm thickness becomes a thinned out, membranous structure of less than 1 cm thickness. The anus, from being a closed opening, becomes dilated to the extent of 2-3 cm. The canal becomes almost a semicircle.

Suction evacuation and curettage

It is a procedure in which the product of conception are sucked out from the uterus with the help of a cannula fitted to a suction apparatus. This improvised method consists of a suction machine fitted with a cannula either plastic or metal available in various sizes.

Indications -

• Medical termination of pregnancy during first trimester (commonest).
• Inevitable abortion
• Recent incomplete abortion
• Hydatidiform mole

Advantages - 

• It is an outdoor procedure.
• Ideal for termination of therapeutic indications.
• Blood loss is minimal.
• Chance of uterine perforation is much less.

Disadvantages - 

• The method is not suitable with bigger size uterus.
• Requires electricity to operate and the machine is costly.