Second Trimester

Blood Type and WinRho
Rh Sensitization


The blood type of 85% of the world population is Rh positive. If you are part of the remaining 15% who are Rh negative, please read this handout.


How might my Rh factor affect my pregnancy?

Rh refers to your blood type. You are either Rh-positive or Rh-negative. For example, your blood type might be A-negative.

The Rh factor can cause problems if the pregnant person is Rh-negative, the other genetic contributer is Rh-positive, and the baby conceived is Rh-positive. It is not possible to know if the baby is Rh-positive until birth.


There are two steps involved in “sensitization” (also known as isoimmunization) when the pregnant person’s blood sees the baby’s blood as foreign:


  1. Transplacental hemorrhage: During pregnancy, although the pregnant person and baby have separate blood systems, blood from the baby can sometimes cross the placenta into the pregnant person’s system.

  2. Antibody formation: Once the baby’s blood has mixed into the pregnant person’s system, the person can become sensitized. This means that antibodies are produced to fight the baby’s blood as if it were a harmful foreign substance. (Antibodies, for example, help us fight infections and viruses and are our body’s way of getting rid of whatever seems harmful to us.) If these antibodies then cross the placenta to the baby, they will attack the fetal blood cells.


Once formed, antibodies are permanent. During the pregnancy when sensitization occurs, the baby is usually born before the pregnant person develops enough antibodies to harm the baby. The concentration of antibodies becomes higher in subsequent pregnancies. Therefore the danger is greater for babies born after you have become sensitized.


What factors can cause Rh sensitization?

Sensitization can also occur after any physical violence, accident (such as a car accident) or procedure that might involve or cause bleeding from the placenta. These include, amniocentesis, chorionic villus sampling, abdominal injury, abruption of the placenta, miscarriage, placenta previa or external version of a breech baby.


Sensitization can occur even if a pregnancy ended in miscarriage, abortion, cesarean, or was an ectopic pregnancy.


How do I know if I have become Rh sensitized?

Your blood can be tested anytime to determine if you have any antibodies.  This is usually done in the initial bloodwork, again at approximately 28 weeks, and then again shortly after the birth.


What happens if I become Rh sensitized?

Rh sensitization can result in hemolytic disease of the newborn. The seriousness of this condition can vary. Some babies have no symptoms. In more severe cases, problems such as hydrops can cause the baby to die before, or shortly after birth. Severe hemolytic disease of the newborn may be treated before birth by intrauterine blood transfusion.


In some babies it becomes apparent during pregnancy, other times, the first sign is jaundice in the first 24 hours, which usually requires a transfusion and intensive care.


An Rh sensitizedperson can be checked during their pregnancy to see if the baby is developing blood disease through the use of amniocentesis and ultrasound.

There are no immediate consequences to the pregnant person if Rh sensitization occurs.


How can I try to prevent sensitization?

The most commonly accepted treatment is injection with Rh(D) immunoglobulin. In Canada, Rh(D)IG is packaged and sold as WinRho.


Although 90% of sensitizations occur during birth, 1-2% occur before the baby is born. Because of this, WinRho is offered at 28 weeks of pregnancy. It is protective till the birth, when there is the greatest risk of sensitization.


After the birth, the baby’s blood is tested for blood type. If baby is Rh+, you will be offered another dose of WinRho within 72



WinRho should also be administered within 72 hours of any other incident or indication (such as amniocentesis, abdominal trauma or bleeding from your uterus).


How effective is the treatment?

WinRho reduces, but does not eliminate the possibility of Rh sensitization. The risk of sensitization after birth of an Rh+ baby is:

  • 7-17% without treatment

  • 1-2% with postpartum treatment only

  • 0.1 – 0.2% with antenatal (at 28weeks) and postpartum treatment


What are the risks of treatment?

WinRho is developed by injecting human volunteer donors (Rh-negative) with the positive Rh factor, then drawing their blood once antibodies have been formed. This blood is treated and screened for viruses (such as HIV and Hepatitis) and concentrated into a serum for injection. WinRho is a human-blood product and therefore is at risk of containing unknown viruses.


Injection of WinRho carries the risk of anaphylaxis, an extreme and very rare allergic reaction.


Some brands of Rh(D)IG, such as RhoGam which is used in the United States, contain the preservative thimerosol, which is a mercury derivative. Mercury crosses the placental barrier. The Canadian version, with the brand-name WinRho, does not contain a mercury preservative


Are there any alternative treatments?

There are no known alternative treatments to Rh(D)Ig injections.




Gestational Diabetes


Gestational diabetes is a condition that can occur in pregnancy where insulin production is dampened so that the levels of blood sugar rise. Some degree of decreased insulin is normal in pregnancy to allow for glucose (sugar) to reach the baby through the placenta and help them grow. Gestational diabetes occurs when there is an overresponse of this physiological event. The cause of this overresponse may be due to hereditary factors (family predisposition) or to lifestyle (diet/activity).


What are the benefits of maintaining stable blood sugar levels?


  • Feel better and have more energy

  • Minimize nausea

  • Minimize strain on internal organs and body chemistry

  • Minimize chances of hypertension

  • Maintain stable internal body chemistry and prevent candida/yeast growth

  • Grow your baby within a normal range, have an easier labor, increase your chance of spontaneous vaginal delivery without the need for intervention

  • Minimize weight gain without “dieting”

  • Return to your pre-pregnancy/ healthy weight easier and more naturally


How can I promote normal blood sugars?


Focus on a variety of healthy foods

As always, eat a variety of wholesome foods: fresh vegetables, fruits, grains, beans, quality dairy and meat (unless you are vegan/vegetarian), as well and unrefined oils and fat.


Balance your meals

Foods should be partnered together for taste, enjoyment but also to reduce a glycemic rise.  For example, combining carbohydrates with protein (salad and fish, rice and tofu), and fruit with fat (pear with nuts, banana and yogurt).  These combinations allow sugars to be released slowly, instead of all at once.


Eat small frequent meals

Eat smaller portions more frequently.  Take the food you might normally eat in three meals and divide it into six, evenly spaced throughout the day. This can reduce digestive stress, and allow your meal to digest more easily, as well as keeping your blood sugar from having wide fluctuations throughout the day.


Be active every day

Developing a daily exercise program is as important as eating well. Being active helps in two ways. First, every time you exercise, you use up blood sugar and keep levels lower for several hours. Exercising for a few minutes after every meal (even just a ten minute walk around the block), when your blood sugar levels are elevated, is an excellent practice. Secondly, exercise that builds muscle will create more cells that use up blood sugar, even while you are sleeping.


Eat less processed, closer to whole and raw

Eat foods in their natural unprocessed form.  For example, whole fruit causes a lower blood sugar rise than fruit juice. Grains cooked until they are mushy cause a greater blood sugar rise than when they are al dente.  Processed foods are in a way pre-digested and breakdown much faster than their whole counterparts, thus quickly creating a sugar rise.  For example, white rice will digest quicker than brown rice.


Reduce stress

Reduce stress, which causes blood sugar to rise. Meditate, breathe, do yoga, get a massage, take a bath with lavender & Epsom salts, ask for support, or whatever it takes.


Be aware that binging – eating a lot of carbs at once, especially high GI foods like fruit, bread, and pasta – can cause sharp rises in blood sugar. Whenever you have a sugar craving or an urge to binge, think about whether you have eaten enough protein in the last day – maybe you are just hungry for more nutrients. Also consider whether you might be dehydrated, as sugar cravings can be disguising thirst.


How might GDM affect me?


The primary risk of GDM is growing a large baby. (On a population level “large” is defined as more than nine pounds, or four kilograms.) If you grow a baby that is larger than you might have without GDM, then you are at increased risk of having a difficult labour or birth. The possibilities include induction, forceps delivery, shoulder dystocia, postpartum hemorrhage and/or cesarean section. Of course there are healthy reasons for having a large baby, such as genetics and good diet, and these are not reasons for concern. By far the majority of large babies are born to people who do not have GDM.


Unlike overt diabetes, which may cause symptoms such as intense thirst, unusual hunger, and passing large amounts of urine, mothers with GDM feel perfectly healthy. After birth, blood sugar levels return to normal right away.


Being diagnosed with gestational diabetes does indicate that you have a high chance of developing adult-onset diabetes within 10-15 years. Knowing this gives you the chance to implement lifestyle changes that may prevent this from happening, (Some people think this fact alone is a good reason to be tested for GDM.)


How can GDM affect my baby?

Besides the effects of a difficult labour or birth, babies born to people with GDM are at higher risk of hypoglycemia after birth making transition for them more difficult. Feeding immediately after the birth can prevent this.

It is believed that complications for both the pregnant person and baby are proportional to the degree of glucose intolerance – the higher your blood sugar measurements, the more at risk you and your baby are.


What are risk factors for GDM?


  • Previous gestational diabetes

  • Previous baby >4kg

  • BMI >25

  • Age >25

  • Sugar in the urine

  • Family history of diabetes

  • Pregnancy induced hypertension

  • Unexplained pregnancy losses


How is GDM diagnosed?

In the clinic: At every prenatal appointment, your midwife will palpate your growing belly, as well as measure your uterine size (symphysis-fundal height) after you reach 20 weeks. You will also be offered testing for GDM between 24-28 weeks, or if you have risk factors, be recommended to have testing done earlier.


1. SCREENING TEST (50 gm Oral Glucose Challenge Test – OGCT)

At the lab: There is a blood test specifically for GDM that is offered between 24 and 28 weeks gestation, although it can be done at any time in pregnancy. It is called the Oral Glucose Challenge Test. You drink 50g of glucose – much like a very sweet, flat, orange soda – and then have your blood drawn 60 minutes later.  If the lab values come back higher than 7.8mmol/l, then the next step is the diagnostic test. The exception is if the values are very high (>11.1 mmol/l) in which case, GDM can be diagnosed with this test.


2. DIAGNOSTIC TEST (75 gm Oral Glucose Tolerance Test – OGTT)

This is similar to the screening test in that it consists of drinking glucose and having your blood drawn. The difference is that this test involves drinking 75 grams after an overnight fast.  Your blood is drawn just before, and then one and two hours after drinking the glucose. Diagnosis of GDM is made if any of the results are higher than normal.


Are there drawbacks to testing?

Some people find consuming the sugar causes them to be nauseous or even vomit. There may also be concerns about the effect on the baby of fasting and then sugar loading. It may help to make your last meal one of high quality protein such as eggs, beans or lentils to aid in stabilizing the blood sugars.


GDM is said to occur in 2-3% of pregnant people, but testing is not considered very reliable. Of the people who test positive, 70% will have babies weighing less than 9 pounds even with no treatment. Also, the majority of babies weighing more than 9 pounds are born to people with normal blood sugars. Research has shown that people with diagnosed GDM – whether or not they receive treatment – have an increased risk of cesarean section without any demonstrated improvement in outcome for the birthing person or baby.


Of note: if you test negative, this does not mean that you are free to eat lots of sugar and forget about good nutrition! Even if you are not diabetic, you can still grow a larger baby by eating a diet full of refined sugars and highly processed food.


What are my options for treatment?

If you are diagnosed with GDM, treatment centres on making lifestyle changes – modifying your diet and changing/increasing your exercise habits.  To help you with this, your midwife will refer you to the Diabetic Clinic.

Counseling at the Diabetic Clinic will include information about how to maintain a Low Glycemic Index diet, and use exercise to keep your blood sugars low. You will be asked to record daily blood sugars for a number of days. Follow-up will depend on the results of these blood sugars – if they are within normal limits, then you likely won’t need further follow-up; or you may need a few adjustments to your regime; your midwife will continue to be your care provider.

In rare instances, you made need insulin to control your blood sugars. Clients who need insulin are under the care of a physician (transfer of care) and your midwife will provide supportive care.


What about follow-up after the birth?

Your baby may have their blood sugar tested soon after the birth, to make sure that they are not experiencing hypoglycemia. (Nursing immediately after birth is the best way to prevent this.)


The standard of care for the pregnant person is to offer a repeat OGTT between 6-12 weeks post-partum to make sure you haven’t developed Type II Diabetes. As you are no longer in our care beyond 6 weeks, we ensure that your family doctor or nurse practitioner is aware of your results and the recommendations of the diabetic clinic.




Preterm Labour


In most pregnancies, labour starts between 37 and 42 weeks after the last menstrual period. Labour is considered preterm labor when it starts before the beginning of the 37th week.


What causes preterm labour?

It is not known exactly what causes labour to start. Hormones produced by both the pregnant person and fetus play a role.  Preterm labor may be a normal process that starts early for some reason. Or, it may be started by some other problem, like infection of the uterus or amniotic fluid. In most cases of preterm labour the exact cause is not known.  Half of pregnant people who go into preterm labour have no known risk factors.


Why the concern?

Growth and development in the last part of pregnancy is critical to the baby’s health. If preterm labour is found early enough, delivery can sometimes be prevented or postponed. This will give your baby extra time to grow and mature. A medication (corticosteroid) can be given to help the baby mature if preterm labour is suspected.


The earlier the baby is born, the greater the risk of problems. Preterm birth, especially very preterm delivery before 30 weeks, accounts for about 75% of newborn deaths that are not related to birth defects. Even “late preterm” babies, i.e. born between 34 – 37 weeks, can have problems such as maintaining a normal body temperature. Thus, if you are planning a home birth but find yourself delivering before 37 weeks, it will be recommended that you birth in the hospital.


Diagnosing Preterm Labour


Signs of preterm labour


  • Change or significant increase in vaginal discharge - spotting

  • Ruptured membranes (your “water breaks”)

  • Vaginal bleeding

  • Low, dull Backache (comes and goes)

  • Pelvic pressure (feels like the baby is pushing down; feels heavy)

  • Abdominal cramping

  • Menstrual-like cramps (comes and goes)

  • Uterine contractions


If you are noticing uterine contractions, cramping or backache:


  • Drink 16 oz. of a non-caffeinated beverage and empty your bladder, then get in a warm bath or lie down, and count the contractions for an hour.  Physical and/or emotional stress can increase the number and strength of Braxton-Hicks contractions (mild, often painless, practice contractions that do not change the cervix!), so the idea is to relax and de-stress.


Call your midwife if:


  • you have six or more contractions in an hour; (about every 10 mins)

  • your contractions/cramps/backache are increasing in frequency, duration or strength

  • you have risk factors for preterm labor, such as a personal or family history of preterm delivery

  • You feel “off,” as if something is wrong



Preterm labour can only be diagnosed by finding changes in the cervix.  However, there is a screening test that can be used to identify clients at higher risk of preterm labour.


Fetal fibronectin is a protein that is often present and can be detected in the posterior fornix (area of the back part of the vagina behind the cervix). The presence of this protein does not predict that you will go into preterm labour as it has a high false positive rate. The presence of blood, semen and a vaginal exam in the previous 24 hrs rule out the use of this test as the results will not be useful.


If there is no contraindication (blood, semen or vaginal exam in the past 24 hrs), this test can be very useful as the absence of the fetal fibronectin protein means that you are very unlikely to give birth in the next two weeks. Usually, your midwife will perform the fetal fibronectin test first (using a q-tip like swab) and then assess the cervix by a vaginal exam afterwards (inserting two fingers into your vagina to feel the cervix). Other times, ultrasound will need to be used to confirm cervical shortening and/or dilation. Usually as swab for GSB status (see Group B Strep) would also be done at this time to guide management of the baby postpartum.


Usually on a routine ultrasound, the cervix length is measured. Any measurement greater than 2.5 cm is considered normal, but shorter than 2.5 cm is considered a risk for preterm labour and  serial ultrasounds will be offered to monitor whether the cervix is continuing to shorten.


All the early preterm labour tests have the goal of identifying those at risk so they can be offered corticosteroids. This medication, given by injection improves the outcomes for babies born preterm significantly and is one of the major improvements in pregnancy care in the past 60 years. This medication can be offered between 24-34 weeks gestation.


What Else Could Be Going On?

The guidelines for when to call regarding preterm labour are rarely preterm labour – because the discomforts of pregnancy are such a close match!


Sometimes, a bladder infection or vaginal infection (yeast, bacterial vaginosis) can mimic symptoms. Sometimes, backache, cramps and intermittent discomforts are the body adjusting to pregnancy, the growth of the uterus stretching the uterine ligaments.




Weight Gain in Pregnancy


What is normal weight gain in pregnancy?

There is a huge range of normal when it comes to gaining weight in pregnancy however, the average weight gain is 25-35 pounds. What and how you eat is as important, if not more, than the actual weight gain. Eat to hunger with healthy and nutritious food and occasional treats.


Many factors influence weight gain: maternal metabolic rate, diet, lifestyle, nausea/vomiting/diarrhea, smoking, degree of swelling, amount of amniotic fluid, and the size of the baby. Age, pre-pregnancy size, parity (number of prior births) and ethnicity also influence weight gain. Pregnancy weight gain patterns, as well as newborn size, often run in families.


What can weight measurements indicate?

The weighing of the pregnant person has become routine in many areas. One of the reasons for this is that as a society we are preoccupied with size and weight. Yet research fails to show that it is an effective way of monitoring the health of the pregnant person and baby.

Weight measurement is only one of many tools that caregivers have. It cannot diagnose a healthy diet. Quality nutrition is one of the most important routes to a healthy pregnancy and birth. More effective tools include regular abdominal palpation of the growing uterus and baby, measurement of the uterine height, and urine dipsticks to diagnose sugar in the urine.

Weight measurement can be useful, once there is suspicion of a developing problem, for further monitoring of such pregnancy issues as intrauterine growth restriction (IUGR), gestational diabetes or hypertension. Of course, these problems are rare, and weight gain by itself indicates very little.


What are the disadvantages of weighing?
  • Overall weight gain may play into negative feelings about body image

  • Since most pregnant people do not gain at a steady rate, this can lead to worry about “too much” or “too little” within a certain time period, only to even out at a later point

  • Reaching a specific number may trigger negative body image issues

  • Prenatal visit time could be better spent on other care


Should I weigh myself regularly?

Regular weighing can be weekly, monthly or every trimester. You should consider regular weight measurements:


  • If you feel it would add to your pregnancy experience – you may want to know how your body is changing

  • If you smoke

  • If you have frequent vomiting or diarrhea

  • If your midwife thinks you have signs of developing gestational diabetes, hypertension or IUGR (interuterine growth restriction)

  • If you have a prepregnancy BMI that is lower or higher than (18.5 to 24.9)

  • If you have had a previous baby who was very large or very small.


Your midwife will discuss the growth of the baby with you, review nutrition and dietary advice and record your weight if you wish to measure it. Otherwise, we will usually only ask for your normal prepregancy weight as part of the initial health history.