Thursday, February 18, 2021

GESTATIONAL DIABETES: SCREENING DIAGNOSIS AND MANAGEMENT

 

Diabetes mellitus an ever increasing disease in the world. It is a chronic disease causing high blood sugars. These cause changes in the big and small blood vessels finally leading to multi organ disease e.g. brain, eyes, heart and kidneys. Type 1 diabetes occurs in children who never produce insulin. Type two occurs in adults and at present it is occurring in epidemic numbers, 1 in 11 people. This increase is in adults. So much Diabetes in the world is due to our life style factors, affluence, and lack of activity even if we have to go to the local post office we take the car. Exercise physical activity transport and too much socialization. Type 3 diabetes is gestational diabetes occurring in women for the first time during pregnancy. This happens in about 7% of women. It becomes type 2 diabetes in large numbers of females depending on their life style, subsequent pregnancies, and weight gain. Pregnancy is classified as dibetogenic. With the increasing numbers of obesity in the world, diabetic pregnancy is increasing in parallel. This is referred as Gestational Diabetes Mellitus (GDM). This has its own problems, increased blood pressure causing a complication called preeclampsia of pregnancy, big babies (Macrosomia) causing need for caesarian section or difficult deliveries, shoulder dystocia (difficulty with delivery of shoulder), intrauterine fetal deaths and so on. With these happening, the World Health Organization (WHO) decided to screen all pregnant women for diabetes during pregnancy.  Those at higher risk are screened on the first visit, others at 24 -28 weeks because the need for insulin during pregnancy increases at this time. (It is also referred as Insulin resistance meaning body’s inability to use Insulin correctly.)  Blood glucose increases in blood, not being absorbed by the body cells, muscles, fat, and liver. The main cause for this is obesity and lack of activity

Why does the need for insulin increases during pregnancy. This is due to hormones produced by the placenta to help with the fetal growth and development. These hormones are estrogens, human placental lactogens, growth hormones and cortisol. These interfere with the body using insulin effectively. It collects in the blood instead of being absorbed by the cells. This is called Insulin resistance as already mentioned. Initially the placenta is able to produce more Insulin. But in the end this fails. Insulin resistance becomes high and GDM starts. The risk factor for GDM are previous GDM, BMR over 25 Kg per sqm, family history of Diabetes in the first degree relative (Mother, Father Etc.) poor obstetric history, previous fetal death, polycystic ovarian syndrome, big baby more than 4 Kg in weight, nationality: Chinese, Indian, Pacific Islander and Blacks and many others. The screening is started on the initial visit in these high risk women.

Different centers around the world perform the diagnosis by different technical details and consider slightly different normal values. Generally a glucose tolerance test (OGTT) is done. Blood is taken while fasting, then 75 mg of glucose solution is given to drink in 5 minutes. After this 3 samples of blood are taken for glucose in I hour, 2 hours and 3 hours .These values should be

1, 5.1mmol/L (92mg/dl)

2,10mmol/L (180mg/dl)

3, 8.5mmol/L (53mg/dl)

If any value is above the normal, a diagnosis of GDM is made. This differs in different centers in different places which creates confusion. In the past and in some places these values were slightly different fasting 5.3 mm/l. 2 hours 8.6 moll/L.  One has to go by what the local value and criteria are. Some places recommend two abnormal values, WHO recommends universal screening of all women at 24-28 weeks of pregnancy as currently GDM is increasing in tandem with obesity in the world. This is due to our prosperity and poor life style factors. GDM causes Diabetes type 2, in future years of life. It is recommended to screen for GDM on first antenatal visit if there are risk factors for diabetes These are obesity, BMI more than 25kg per sq. mtrs, family history of first degree relative with diabetes, previous stillbirth, shoulder dystocia, macrosomia baby bigger than 4000gm, ethnicity (Chinese, Indians, African Americans, Hispanic), age older than 35, weight gain of 11lbs since age 18 years.

GDM effects Pregnancy by maternal complications such as high blood pressure, preeclampsia, difficult delivery, need for induction, and caesarian section. It also causes big babies (MACROSOMIA), fetal abnormalities, still birth, shoulder dystocia (difficulty with the delivery of the shoulder) nerve palsies, fractures. These babies have hypoglycemia at birth and hyperbilirubinemia (neonatal Jaundice) these babies grow to be obese and hyperglycemic, develop diabetes later in life.

HOW to deal with GDM

Good management results in good results.  It is worthwhile to involve a diabetic physician a dietitian and may be a midwife. Proper care may, prevents preeclampsia, macrosomia, shoulder dystocia, any fetal injuries, need for induction or caesarian section. One basic rule in women with GDM is never let them go over due dates.

Glucose monitoring

Women should start monitoring fasting and 1- 2hours post prandial blood glucose the values accepted differ, 5.3 mmol/L(latest 5.1). 2hours 6.7 mmole/L.

The simplest treatment starts with life style changes, diet on the advice of a dietitian. Low GI carbohydrates are advised. Regular exercise, walking is best.

One recent  research has suggest that an  active exercise program in  the first trimester of pregnancy including walking, low impact aerobics, stationary bicycle and swimming can reduce the risk of GDM. If life style changes and diet alone cannot change the  blood sugars as desired, then some pharmacological drugs are added. Metformin is one such oral drug .  It is only used in some countries not in most. Insulin is the preferred drug treatment. Insulin is used when diet and exercise does not control diabetes as desired. 0.7 to 1, unit of Insulin is started per kg body weight of the women in question. Half of this dose is given as long acting Insulin last thing at night. The other half is given in three divided dosage as short acting Insulin with three meals, sometimes they can have some hypoglycemia in the middle of the night but it is not frequent or very severe. These dosages are adjusted as need be in each individual woman until the blood sugars are at the desired level as mentioned.

Special fetal care is provided for mothers who have GDM.  This can involve regular fundal height assessment fluid around the baby and fetal heart. This can be assessed by the clinician particularly an experienced one. This is often done by ultrasound as well twice weekly or weekly by biophysical profile from 32-34 weeks on wards. Depending on how well is your GDM is controlled. And if you are on Insulin. This includes fetal heart monitoring as well.  Fetal weight is estimated by ultrasound these days.

The other very important decisions are when and how to deliver this woman. If the GDM is well controlled by diet and exercise they can have a normal birth at term. Do not allow them to go past the due dates. Women are induced between 37-39 weeks if any other complications are present or DGM is not greatly controlled. If the fetal weight assessment is 4500g a caesarean section is advised[AP1] [AP2] [AP3]  they are made aware of limitation of weight assessment, particularly if they have a high BMI themselves.

During labor fetal heart monitoring is done continuously. Mother’s blood sugar is maintained by intravenous glucose and Insulin as required.  A pediatrician is invited to be present for delivery to look after the baby as they can have hypoglycemia or acidosis. Mother’s insulin is often not required after delivery. An OGTT is performed for the mother 6-12 week’s post-partum. Women are advised to breast feed as this is best both for the mother and the baby as it helps with minimizing weight gain. It is best to avoid weight gain and be active as this helps not getting Diabetes in future. An OGTT needs to be performed every year, some say every 3 years which I think is not enough. It is best to avoid too many pregnancies but that is individual choice.

We have very good news for the future, worked out by some great research scientists. They have found that the Tymus gland in our body involved with our immune system has a big role in pregnancy by producing cells called  TREGS via Rank are deficient in women who suffer repeated miscarriages and GDM . They also been trying to use them in clinical trials, so we can get rid of two very big problems in women. Great news.


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