Can you drive when you are pregnant?

The law does not prevent you from driving when you are pregnant unless you can’t do so safely, i.e. you cannot control the car. The physical changes and challenges you face when being pregnant might encourage you (or force you) to stop driving towards the end of your pregnancy:

Comfort: getting in and out of some cars will be difficult and it will be harder to get the seat belt fastened, especially if you are wearing winter clothes, too. Ensure that the lap part of the belt sits low across your hips and the torso part is tight against your right shoulder and sits between your breasts. You cannot get an exemption from wearing a safety belt when you are pregnant. Some pregnant drivers report that once the pregnancy is fairly advanced they can no longer twist their body to look out of the rear window when reversing, or over their shoulder to check their blind spots.
Tiredness: if pregnancy has disrupted your sleep bear in mind that driving tired is like driving drunk.
Morning sickness: if you feel sick or ill enough for it to be a distraction or for you to need to pull over in a hurry, avoid driving during those times.

Your general risk of being in a car crash does not go down when you are pregnant; some expectant mothers choose to limit their in-car time simply to reduce the risk.

Riding a motorbike when pregnant

Again, there is no law against riding when you are pregnant. Some obstetricians and doctors advise against riding a motorbike while pregnant because:

it can be jarring, depending on your bike and the quality of the roads near you, presumably
loud – it is possible to damage your foetus’s hearing, and some motorbikes can produce up to 100dB which, over a longer ride, will damage the rider’s hearing, too (sustained noise over 85dB damages hearing)
any vibration is not good for the baby and can, in extreme cases, cause a miscarriage.

It is up to the rider to determine what level of risk they are willing to take as the likelihood of serious injury in a motorbike accident is much higher. Heavily pregnant women may have to adjust their riding position depending on the bike they ride (e.g. cruiser vs sports bike) as not to put pressure on the baby, and will almost certainly need to adjust the fitment of any protective clothing. Women that are susceptible to leg cramps due to the pregnancy may find them worse in a riding position.

Riding as a pillion passenger carries the same risks.

Foetal injuries in car crashes

The mother’s body is restained by the seat belt but the foetus is not. There is a risk that the placenta can become detached with the force of an impact. This means the baby will not be able to get enough oxygen. There is a minor risk that the baby’s head could impact the mother’s pelvis, leading to head injuries.