Oxytocin: The post-birth life saver

In 1909, one Sir Henry H Dale discovered that an extract from the human pituitary gland caused the uterus of a pregnant cat to contract. I won’t even ask how this man, who changed the world of women in such a remarkable way, went about arriving at this discovery. Let’s just say that he opened the door to the second most important invention that saves the lives of mothers today — the first being antibiotics.

Sir Dale discovered the naturally produced pituitary hormone. He named it “oxytocin”, derived from the Greek words “quick birth”. He further discovered that every mammal produced the same exact hormone, and it had the same effect on the uterus. In 1911, he further discovered that this hormone also facilitated the release of the mother’s milk by causing contraction of the smooth muscle cells in the breast, causing milk to be released from the nipple, the milk let-down.

It took almost five decades before Vincent du Vigneaud, an American biochemist obsessed with figuring out the chemical structure of substances, managed to figure out the nine amino-acid structure for oxytocin. He did not stop there but went on to recreate it in the lab, birthing synthetic oxytocin that revolutionised obstetrics forever. As an indication of just how momentous his discovery was, du Vigneaud went on to win a Nobel Prize for Chemistry in 1955. 

Oxytocin, available all over the world and marketed as Pitocin or Syntocinon, has gone on to define our craft as obstetricians in multiple ways. It has been used for decades to trigger onset of labour in special circumstances where needed. To mothers in labour, it is the much-dreaded Syntocinon drip that is used to assist with the progress of labour when the contractions are too slow or not strong enough, avoiding unnecessary delays, fatigue and surgical interventions.

Its most revolutionary role has literally been in preventing death. In Kenya, the leading cause of death remains postpartum haemorrhage. In a country where approximately 8,000 women die every year from childbirth-related complications, taming postpartum haemorrhage must remain top of the agenda. This figure could be way worse, were it not for the trusty little hormone in a vial.

The standard of care world over is that immediately the baby is born, the mother is given a shot of oxytocin. The sole purpose of the shot is to stimulate the just-emptied uterus to contract very strongly, literally choking off the multiple blood vessels that are bleeding into the uterine cavity after the placenta comes off, and forcibly stopping the bleeding. 

This immediate support given to the uterus has saved millions of lives from life-threatening bleeding. Where the shot is not sufficient, the oxytocin is added to an intravenous fluid solution and infused into the mother slowly. The versatility, tolerability and safety profile of this century-old wonder drug is something worth celebrating. 

Samson* can attest to this. He had brought his wife Rhoda* to the labour ward for the delivery of their third baby. She went into labour two weeks earlier than anticipated. It was in the wee hours of the morning when they made their way to the hospital, leaving their two older children in bed, under the care of a 17-year-old niece. 

Rhoda still had a few more hours to go and Samson opted to go back home and ensure the children were alright and ready for school in time; and to also have a shower before getting back to the hospital. However, the new baby surprised him. When he got back, Rhoda had already delivered. She had precipitate labour, an unexpectedly fast labour that unfortunately comes with a high risk of postpartum haemorrhage. 

He found his wife in bed, cuddling their adorable newborn daughter, a picture of contentment. She was breathtaking and he was overjoyed. He held her close while his wife rested.

Suddenly, Rhoda turned around in bed and lay on her back. She told Samson that he needed to call the nurse because she was bleeding a lot. The nurse who responded quickly slipped on her gloves while shouting for help. Samson was asked to step out of the room while a team converged at the bedside. For the next half hour, he was a mess. He held tightly onto her and prayed for his wife to be OK.

After what looked like eternity, he was allowed to come into the room. Rhoda was stable, with an oxytocin drip running into the cannula on her left hand. She reached out to him with the free hand and gave him a reassuring squeeze. She was going to be just fine. Oxytocin, the first line of defence against postpartum haemorrhage, had come through for her. 

It has been almost seven decades of exemplary service from oxytocin. It does not suffer pharmaceutical challenges such as resistance, and it remains affordable. However, it requires refrigeration, hence calling for observation of the cold chain to ensure proper storage and distribution. This becomes its weakest link because women have died as a result of being given oxytocin that was exposed to unfavourable temperatures in transport or storage, causing it to denature. The importance of having power backup in health facilities to keep refrigerators running during power outages cannot be overstated.

In the quest to address these challenges that may lead to threat to maternal outcomes, we now have the heat-stable variant of oxytocin known as carbetocin. This is not yet widely available due to the cost but it is a dream for mothers in remote, rural facilities that may still lack access to consistent electricity. 

The greater the arsenal for the protection of women against postpartum haemorrhage, the closer we are to eliminating preventable maternal death. However, all these will remain a pipe dream if we do not invest in ensuring all women in labour have access to this molecule. Let us keep our mothers safe!

Dr Bosire is an obstetrician/ gynaecologist