Do you have impaired kidney function and a strong desire to have children? But are you unsure whether pregnancy is possible under these circumstances? This article informs you about what you need to consider and what difficulties and complications can occur. You will also find out what the differences are compared to women on dialysis or women who have had a kidney transplant.
Can I get pregnant at all with existing renal insufficiency?
The good news from the start: yes, in principle you can get pregnant even with existing kidney function impairment. However, kidney function does affect a woman's fertility. A typical laboratory value that can be used to check the function of your kidney is the amount of creatinine in your blood (=serum creatinine). Creatinine is actually a "waste product" in your body that is produced when your muscles produce energy and is normally excreted by your kidneys. If your kidneys don't work like they used to, they can't clean your blood of creatinine as well. Therefore, more creatinine remains in the blood and the serum creatinine level increases. Normally, this level is between 0.5 and 0.9 mg/dL in women. If your kidney function is chronically impaired (>6 months), your probability of becoming pregnant is often also somewhat lower.
At the same time, the risk of complications - both for the unborn child and for the mother - is increased. Therefore, women with impaired kidney function are advised to plan their pregnancy in advance, if possible. To do this, it is best to contact a so-called prenatal center, where gynecologists, nephrologists and neonatologists work closely together and can give you the best possible advice. Your treating medical team should be able to help you find such a center.
How many pregnant women have kidney disease?
Statistically, up to 3% of women of childbearing age have impaired kidney function (=Chronic Kidney Disease, CKD). The proportion of pregnant women with impaired kidney function is about the same. As you can see, chronic kidney disease is by no means a reason for not being able to carry a child to term. Ideally, therefore, you should talk to your medical team so that your family plans can be medically coordinated and a possible pregnancy can be optimally adapted to your limited kidney function.
What are the risks of pregnancy with kidney disease?
You now know that pregnancy is generally possible with existing kidney disease. However, under these conditions it is considered a so-called high-risk pregnancy, which should be closely monitored. Basically, a high-risk pregnancy is not a reason for you to worry. It only means that the risk of complications is increased. This also applies, for example, to women with diabetes mellitus or multiple pregnancies (e.g. twins). The dangers for the unborn child include above all an increased rate of premature births and miscarriages, as well as a low birth weight.
For the mother, there may be a worsening of kidney function and blood pressure levels during pregnancy. There is also an increased risk of blood clotting disorders such as the formation of blood clots (=thromboses), although this is generally increased for all women during pregnancy.
In addition, the risk of developing preeclampsia is increased in women with renal insufficiency during pregnancy. Don't worry, no one pronounces this word correctly the first time. Colloquially, it is therefore also referred to as "pregnancy poisoning". The first signs are high blood pressure (=hypertension), as well as protein in your urine (=proteinuria). Preeclampsia poses an additional risk of complications during pregnancy - both for the mother and the child. However, regardless of kidney function, three to seven pregnant women out of 100 develop preeclampsia. As you can see, pregnancy itself carries certain risks that are completely independent of your kidney function. Nevertheless, the vast majority of children are born completely healthy. So don't be discouraged!
What blood values should I pay attention to in relation to pregnancy with kidney disease?
To assess your personal risk of pregnancy complications, a few important parameters can help. You are probably already familiar with some of the laboratory values. Don't worry, your nephrology team will certainly help you interpret these values.
1. Creatinine & GFR
To assess the risk of pregnancy in the presence of renal insufficiency, the main parameter used is the creatinine level in the blood. As mentioned at the beginning, creatinine is a breakdown product that occurs naturally in your body and is then excreted by your kidney. The logic is quite simple: when the function of the kidney decreases, the amount of creatinine in the blood therefore increases. As you probably already know, the degree of kidney dysfunction is classified, among other things, by the so-called GFR (=glomerular filtration rate). This is a calculated value that shows how much blood per minute is cleansed by your kidney. The higher it is, the better. During pregnancy, however, your body is working for two living beings. In the course of this, various adaptations occur. For example, it is quite normal that your kidneys receive more blood during pregnancy. This automatically increases your GFR value. According to the motto: if more blood flows through, more can be cleansed. In this case, however, this has nothing to do with your kidney function actually improving. The GFR is usually calculated by complicated formulas based on your creatinine, gender and age (this is called eGFR). However, these formulas are not specifically designed for pregnant patients and may give incorrect eGFR values during pregnancy.
2. Creatinine clearance
Since your calculated GFR value can be falsified by pregnancy, the so-called creatinine clearance plays a greater role. The calculation of creatinine clearance takes into account the amount of creatinine excreted in the urine over 24 hours. In other words, it measures how much creatinine leaves the body through your urine in an entire day. This measurement allows a relatively accurate calculation of the GFR despite pregnancy and thus also an assessment of your kidney function.
3. Protein in the urine (=proteinuria)
The amount of protein in your urine is also used to estimate your individual risk of pregnancy complications. This value also provides information about your kidney function.
4. Blood pressure
Another important aspect that affects the success of your pregnancy is blood pressure. Optimally, your blood pressure should be in the normal range, i.e. below 135/85 mmHg. Blood pressure values above 140/90 mmHg should be discussed with your medical team. There are certain blood pressure medications that you can take during pregnancy. The ones you took before pregnancy are usually not among them. Therefore, it is especially important to have your medications adjusted by your medical team before you become pregnant, but at the latest as soon as you know that you are pregnant.
How can I improve the success of my pregnancy?
As you can see, the risk of pregnancy complications depends strongly on your kidney function. If you want to have a child, talk to your nephrologist as early as possible. Then you can create the best possible conditions together and thus increase the probability of a successful pregnancy. As already mentioned at the beginning, it is best to contact a prenatal center where doctors from different specialties work closely together to provide you with the best possible support.
Since a pregnancy with existing renal insufficiency is considered a high-risk pregnancy, you will have to go to more frequent check-ups than other pregnant women. To be more precise, the check-ups will take place every 2 weeks until the 30th week of pregnancy and once a week thereafter. There, your kidney function, blood pressure and the growth of your child - or in the case of multiples, of your children - will be monitored in particular. In this way, possible challenges can be identified and treated at an early stage.
But you can also actively contribute to a successful pregnancy by following a lifestyle that is as healthy as possible. This includes regular exercise (unless otherwise recommended by your medical team), healthy eating, sufficient sleep and, of course, avoiding smoking and alcohol. All of this will have an additional positive effect on your blood pressure, which plays a major role in the development of pregnancy complications associated with renal failure. If you are also taking medication to lower your blood pressure or for other reasons, please check with your doctor to make sure that you are allowed to take it during pregnancy.
Pregnancy during dialysis and after kidney transplantation.
If the kidneys fail (almost) completely, a kidney transplant is performed in most cases. If no suitable organ is available or a transplant is not possible or desired for another reason, dialysis takes over the purification of the blood. What effects can this have on a pregnancy later on?
Pregnancy is much rarer in women on dialysis compared to women with, for example, low-grade renal insufficiency. The reason for this is the significantly reduced fertility in women with kidney failure. Only about one-tenth of women of childbearing age who require dialysis still produce healthy eggs. In addition, the risk of pregnancy complications increases significantly compared to early stages of renal failure.
If a kidney transplant is performed, the situation improves: fertility increases and approximately 33 per 1000 of kidney transplanted women of childbearing age become pregnant (compared to 100 per 1000 of kidney healthy women). However, pregnancy under these conditions is also still considered a high-risk pregnancy. This is because there is still a higher likelihood of preterm birth and of developing preeclampsia. In addition to the risks to mother and child, there is also the risk that the donated kidney will be rejected by the body. To reduce the risks to mother, child, and the new kidney, pregnancy should not occur until at least one to two years after successful organ transplantation and kidney function should be optimized as best as possible (ideally creatinine level <1.5 mg/dL).
In addition, people with a transplanted kidney must take relatively strong drugs - so-called immunosuppressants - for the rest of their lives. These prevent the kidney from being attacked and rejected by the patient's own body. For pregnant women, there are special recommendations as to which immunosuppressants may be taken. Therefore, pregnancy should also be planned early after a successful kidney transplant.
As you can see, you are not alone with your questions and concerns. So do not hesitate to ask your nephrologist if you are planning to become pregnant with kidney failure.
