PROBLEM PREGNANCIES: ABNORMAL PRESENTATION. MULTIPLE PREGNANCY.

Abnormal presentation

‘Presentation’ means the part of the baby that passes through the birth canal first. Normal presentation is head first, facing backwards, and with the neck bent forward so that the crown leads the way through the birth canal. With the head in this position, its narrowest diameter passes through the pelvic outlet.

The most common abnormal presentation is breech, which is bottom first. There are two main reasons why breech presentation causes problems in delivery. First, the soft breech is effective as a dilator of the cervix sol the first stage of labour is usually prolonged. Second, the largest and least compressible part (the head) comes last and may have to pass through an inadequately dilated birth canal. When the head comes first it has plenty of’ mould to the shape of the pelvic during the first stage of labour: note breech presentation. If the head won’t fit through the pelvis, labour will be obstructed. If the body is already delivered,this is a serious problem.

Some foetuses in the breech positionwill spontaneously turn before labour begins, and sometimes a doctor or midwife can turn a breech by manipulations through the mother’s abdominal wall.

A breech delivery will need more intervention and birth injury to the baby more common, even in the best hands. If breech is suspected and confirmed ultrasound before labour commences, caesarean delivery is often advised, especially if the mother’s pelvis is smaller average. In vaginal breech delivery, forceps are usually needed to deliver the head and protect it from injury due to сcompression.

Less common abnormal head presentations include positions of the foetal h” (such as face or brow first, or the head facing the mother’s abdomen rather than her spine) that don’t direct its narrowest diameter through the mother’s pelvic оoutlet. Usually the head can be manipulated into the most favourable position for livery – facing the mother’s spine with crown coming first.

Shoulder presentation is rare, and usually results from an abnormality of the uterine cavity. Transverse lie describes a foetus lying sideways in the mother’s uterus so that its back or side lies over the cervical outlet. Delivery in these positions is impossible and if the foetus can’t be turned, caesarean delivery is the only answer.

Multiple pregnancy

The chance of a twin pregnancy is one in ninety. With triplets it’s one in about 8000; it’s one in about 750 000 with quadruplets. Multiple pregnancy is more common after some treatments for subfertility such as IVF, GIFT and those that stimulate ovulation.

Multiple pregnancy is suspected when die uterus enlarges more quickly than expected.
It can be confirmed by ultrasound. The problems of multiple pregnancy
(in addition to the discomfort of having an extra ‘passenger’ in your uterus) include increased risks of pregnancy-induced
hypertension, pre-term delivery, abnormal presentation, difficult delivery and babies with a low birth weight (sometimes one twin much smaller than the other).

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