PRETERM LABOUR

Babies born more than 3 weeks early (preterm) and particularly those born more than 12 weeks before time (extremely preterm) may have medical problems that are caused solely by the prematurity. Pregnant women at particular risk of preterm labour can be identified and should receive increased prenatal care. Some interventions have been shown to be effective in preventing preterm birth. When preterm labour nevertheless supervenes, prompt recognition and comprehensive management can materially improve long-term outcome for the newborn infant.

Prevention

The preterm ("premature") infant commonly suffers disturbances in many body systems, and some are life-threatening or cause permanent damage. Pregnant women who have an increased risk of preterm labour require more intensive and specific prenatal care¹.

In cervical incompetence the cervix is unable to support the developing fetus to maturity because of pathological overstretching of the cervical canal (channel). Traditional cerclage (purse-string) has been shown ² to have material benefit in only about 1 in 25 cases, at a cost of increased medical intervention and infection after delivery.

As might be expected, the most fertile areas for successful medical malpractice action are failure to diagnose or treat causal infections³. In particular, failure to detect and treat maternal Group B ß-streptococcal colonisation(GBS) will prove a successful litigation strategy in some cases of preterm labour.

Bacterial vaginosis is a sexually transmitted disease that causes nuisance symptoms in the nonpregnant woman. In subsequent pregnancy it should be specifically excluded by vaginal swab or treated if found. There is some evidence⁴ that such intervention will prevent preterm birth in some such women, particularly those with a previous history of preterm labour.

If significant numbers of a single variety of bacterial germ are found in the urine of a well woman (asymptomatic bacteriuria), there is an increased risk in pregnancy of symptomatic kidney infection and preterm labour. There is some empirical support⁵ for reduced probability of both complications if the germ is eradicated with antibiotics.

Management

When preterm labour nevertheless supervenes, prompt recognition and comprehensive management can materially improve long-term outcome for the newborn infant. Where onset of preterm labour cannot be prevented, failure to educate the pregnant woman in the warning signs, or insufficiently prompt action¹ when she reports them, may provide a viable cause of action. Timely intervention may materially reduce the severity of the consequences caused by the premature birth.

Attempting to stop contractions is a traditional approach to preterm labour. There are specific contraindications⁶ to such tocolysis - mainly situations in which prolonging pregnancy may be harmful to the mother's health, and fetal conditions that render greater maturity unnecessary.

Current tocolytics - magnesium sulphate, Ritodrine, and beta-agonists - have not been shown to have a material effect in delaying delivery⁷ and a Systematic Review⁸ is in progress.

Conversely, corticosteroid (typically betamethasone) medication given to the mother at least 6 hours before delivery causes a 50% overall reduction in Idiopathic Respiratory Distress Syndrome (IRDS), the breathing problem that commonly affects preterm newborns and infants of diabetic mothers⁹. The immature fetus has not yet developed the detergent surfactant that prevents stiffness in the lungs of the infant born at term. Thus, the infant of a mother denied prompt and comprehensive management of preterm labour may suffer unnecessarily severe IRDS and its potentially life-threatening consequences.

Outcome

Although the survival of infants born at between 22-25 weeks gestation (15-18 weeks early) improves with each additional week of maturity, the rate of neurological and developmental disability remains fairly steady at 30-50%^{9 []}. 

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