They place yellow flags on the side of major roads to literally flag down passing truck drivers.
The drivers transport the women to hospital, which can sometimes be hundreds of miles away.
The scheme follows an agreement between villagers and drivers' unions.
Previously, many pregnant women faced enormous difficulties trying to get to hospital if they suffered any complications.
There are no ambulances and taxi drivers often refuse point blank to take expectant mothers in their cars. Others raise fares so high that the women are unable to afford the journey.
Taboos
"The drivers do not want to take these pregnant women," said Professor Angela Kamara, a leading campaigner for safer births in the region.
"They have many taboos about women delivering in their cars. In certain societies, the drivers have to perform rites to cleanse their vehicles.
"In the odd instance, should the women die in the vehicle that's a big issue because the drivers are usually just put into jail by the police."
Infant and maternal death rates are often high in some parts of the region, specifically because women have no way of getting to hospital.
The yellow flag scheme by comparison has helped to save countless lives.
Union agreement
Pramilla Senanayake, of the International Planned Parenthood Federation, said the scheme was devised by villagers.
"They discussed with the lorry drivers' union whether lorry drivers who drive between big cities carrying ground nut and oil might in fact be mobilised to help transport women. The lorry drivers said: 'Sure, but what can we do?'
"The villagers replied saying: 'If there's a woman in difficulty in a village - and the village could be a mile away from the main road - what we will do is get her family to plant a yellow flag on the main road.
"'Every time you drive up and down and you see a yellow flag you will know it's a woman in trouble and then you enquire as to who needs help. We will bring her to the lorry. Can you take her the 200 miles?'"
Ms Senanayake said drivers were very supportive and have helped to save many lives.
"They were delighted to be able to help and we reduced maternal mortality significantly because of that," she said.
This story is featured in the radio programme Health Matters on the BBC World Service.
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