www.diabeticretinopathy.org.uk

Pregnancy and diabetic retinopathy

David Kinshuck

 

Pregnancy

Pregnancy may cause a rapid increase in the progression of diabetic retinopathy. That is, if a woman has mild retinopthy, it may progress into a much more severe form in a short time during pregnancy. This may be very serious indeed. see .

Nevertheless, good diabetic control during and of course before the pregnancy prevent this increase in retinopathy, or at least make it less severe. Good control helps, with other reviews here and here.

NICE reviews how diabetes should be controlled during pregnancy 2008.

 

What does this mean in practice? Comments for women:

Generally you will only get retinopathy after 14 years or more of diabetes, with mediocre control. Good control will mean that it may take 20 years or longer before retinopathy starts. Conversely, very poor control may cause retinopathy development in less than 14 years.

So if you have no retinopathy before pregnancy, and your control was not been perfect before the pregnancy, occasionally retinopathy may develop during your pregnancy. Even proliferative disease can develop towards the end, perhaps at around 30 weeks, and laser will be needed URGENTLY. The retinopathy can progress very quickly indeed, so many laser sessions may be needed.

If there is pre-proliferative disease before pregnancy, this will certainly progress to active proliferation...lots of laser will be needed. Generally laser will be needed (in a woman with pre-proliferative disease) as soon as she is found to be pregnant. Progression can be rapid.

Laser is just as easy during pregnancy. You sit at the slit lamp laser...being pregnant makes little difference. Naturally the ophthalmologist must be told if you are pregnant. The drops used to dilate the pupils are generally very safe, but remind the doctor you are pregnant so you do not get too many drops (tropicamide1% & phenylephrine2.5%, and local anaesthetic drops).

If you have well-controlled diabetes before your pregnancy, with an HbA1c less than 7%, and you have no retinopathy, you need retinal checks 3 monthly during your pregnancy. Often these are carried out by your diabetologist. Most women will attend a joint clinic attended by the obstetrician expert in diabetic pregnancies, and a diabetologist, so this does not usually need any extra visit. 3 monthly checks suffice normally. Screening photos are needed as below.

If you have some retinopathy before pregnancy and you were not well controlled, checks are probably needed by the ophthalmologist expert in retinopathy. Generally these will be needed monthly.
My recent experience has identified 2 patients deteriorating in later pregnancy, 26 weeks on, with even more progression at 30 weeks. Both women had previously poor control of their diabetes, and one smoked. Progression is likely to be even more rapid if control was poor and then improves, although in the long term good control is vital, especially for the baby.

Type 2 diabetes is a major problem in pregnancy, but few type 2 patients have retinopathy, so the eyes are not usually the main concern...the main concern is the health of the baby.

If the HbA1c drops >2% then the retinopathy may progress rapidly, and extra screening every 3 months for one year might be helpful. A low HbA1c should take priority as it will help the baby.

 

Comments for professionals

Of course, every woman is different. Generally progression of retinopathy will be more rapid if woman is badly controlled, and poorly controlled before the pregnancy. Retinopathy is unlikely if the woman has been diabetic less than 14 years, but this depends on the control of the diabetes.
The progression is linked to circulating growth factors, almost certainly IGF1. There is no medical treatment (just laser), other than keeping the blood pressure lower, and the diabetes well controlled. However, this paper says the IGF1 system is not involved (I believe the former paper.).
Previous pregnancies are not quite as relevant....just because the last pregnancy was fine with no retinopathy progression, does not itself indicate what will happen next time. (Of course, pregnancies go better if a woman has well-controlled diabetes, and so previous pregnancies occured without problems this suggests better diabetic control.) See.

Pregnancy may cause a deterioration in renal function as well as increasing retinopathy see.

It is very likely that decrease in renal function also exacerbates retinopathy in the none-pregnant, possibly by means of increasing blood pressure.

The retinopathy may progress in the year after delivery. This paper is important. Laser may be needed with careful follow up during this year.

Glucose monitoring is helpful in pregnancy (BMJ 2008)

 

Screening

Screening and pregnancy is very well reviewed here ... subscription needed. If retinopathy is not present just before pregnancy, rescreening is needed at 28 weeks. ~10% of women will develop retinopathy, but not usually severe enough to need laser. If retinopathy is present at the onset of pregnancy, screening is needed at 16-20 weeks, AND 28 weeks. Tropicamide drops to dilate the pupil.

Here is our 2014 pathway:

 

screeing pathway in pregnancy

Treatment..laser or intravitreal steroids

Laser

Laser is very effective in slowing retinopathy, and MUST NOT BE DELAYED until after the pregnancy. Eyes can deteriorate in a week, and bleed very quickly (a vitreous haemorrhage). Often many laser sessions are needed. So with 1000 laser burns in each eye per session, six sessions or more may be needed, per eye. Sessions may be needed on consecutive days. (Whereas if not pregnant much longer gaps between laser sessions may be fine.)

Anti-VEGF drugs are generally not used as it is not certain they are safe.

 

Intrvitreal steroids

These may be helpful, see.

 

Aspirin

Often a woman needs aspirin during pregnancy. This is not a problem until there are retinal new vessels. Aspirin certainly increases the risk of bleeding. This is not usually a problem until late in pregnancy. At about 30 weeks if new vessels are present, bleeding is inevitable. At this stage the obstetrician must advise: clearly the baby must take priority, but it is a balance of risks, what is best for the baby versus the increase in risk of retinal bleeding in the mother.

This paper suggests retinopathy is not a risk factor for retinopathy, but this is not the general experience. I wonder if this author's patients were exceptionally well controlled before pregancy.

 

Advice in the UK versus other countries, and termination of pregancy

Comments on this page really relate to my experience in the UK. But in developing countries, or really in any woman with poor diabetic control, this is an extremely serious problem. But if the diabetes has been extremely well controlled, as suggested (paper) retinopathy progression is a less serious problem.

In Western Countries termination of pregnancy is not routinely recommended, as laser treatment is so successful. It is accepted that a woman's sight may be reduced after retinopathy development and laser. As regards to termination, individual advice is crucial.

Thus if a woman has pre-proliferative (moderately severe non-proliferative) retinopathy, eyes can be lasered as soon as the woman is pregnant. Even so, sometimes the retinopathy may get 'out of control' causing vitreous haemorrhages. But generally the haemorrhages will not be that severe and will clear to allow laser treatment.

In a highly skilled obstetric unit early delivery at 32-34 weeks may be helpful if the retinopathy is very active and bleeding. As with many aspects of medicine, expert advice for the individual patient is the best way forward.