Pee positive

What is it about urine that tells us all we need to know about what’s going on inside our bodies? Tracey Hawthorne finds out

CONFIRMING PREGNANCY from urine dates back to Egyptian times, when women peed on crop seeds in the belief that if they grew, so would a baby. These days, we’re more familiar with the “peeing on a stick” home-pregnancy-test method, and similar tests carried out in clinics and doctors’ rooms. Following sex, the fertilised egg (which was released from your uterus into one of your fallopian tubes during your monthly ovulation) slowly makes its way to your uterus. This can take up to eight days, and when the mass of cells that will soon become an embryo reaches the uterus, it implants itself in the endometrium, or uterine lining. At this point, some cells break away and burrow further into the uterine wall – these will eventually become the placenta, the lifeline between you and your growing baby. Throughout your pregnancy, your baby’s placenta will supply nutrients, water, oxygen and antibodies against diseases, and get rid of waste such as carbon dioxide. From the very beginning, these placental cells begin producing the hormone human chorionic gonadotropin, or hCG. The levels of hCG double every 72 hours for the first eight to 11 weeks of pregnancy – in other words, from very soon after conception, there’s an ever-growing volume of hCG in your system. And it’s the volume of these hormones, excreted in your urine, that announce if you’re pregnant or not. But your urine tells lots of other tales – particularly about your health and that of your baby. Urine tests, which are easy to do and don’t cost much, “can warn the doctor about problems such as diabetes, urinary-tract infection and preeclampsia, or high blood pressure in pregnancy, which can then be managed before they cause complications”, explains Dr Josh Matambo of the Essence Women’s Centre in Newcastle, KwaZulu-Natal.

HOW, AND HOW OFTEN, IS YOUR URINE TESTED IN PREGNANCY?

“Urine tests are a routine procedure done routinely at every antenatal checkup,” Dr Matambo says. “You simply collect a sample of your urine [see box], which the doctor then tests using a dipstick.” The dipstick is a specially treated stick that changes colour according to what substance with which it comes into contact. The repeated tests at every check-up help the doctor to monitor patterns in the urine results and give a more complete picture.

WHAT IS THE DOCTOR LOOKING FOR?

“Proteins, especially later in the pregnancy, may signal pre-eclampsia or a kidney disorder, and glucose [sugar] could mean gestational diabetes,” says Dr Matambo, adding that there are various other substances that could indicate problems such as infection.

These include leukocytes (white blood cells) and blood in the urine. “Other tests can also be run, to check for ketones, bilirubin and urobilinogen,” he adds. Ketones could indicate that you’re not getting enough food (or perhaps losing vital nourishment through vomiting), while bilirubin and urobilinogen can indicate liver problems or a blockage of the bile ducts.

“A urine microscopy can be done if the doctor is concerned about repeated abnormalities in the dipstick test,” Dr Matambo says. Examination of the urine under a microscope could reveal crystals, casts, bacteria or yeast, all of which can be important diagnostic clues.

DOES TIME OF DAY OR WHAT YOU’VE EATEN AFFECT THE OUTCOME OF THE URINE TEST?

Not generally, but according to the doc, “Drinking a large amount of water up to an hour before collecting the urine may dilute the urine, and this could impair the result; similarly, drinking sweet drinks may result in some glucose in the urine, which could cause the doctor to suspect gestational diabetes.”

WHY DO YOU HAVE TO HAVE A URINE TEST WHEN YOU’RE IN LABOUR?

“Labour, and especially premature labour, can be brought on by a urinary tract infection, and if this is the case, identifying the problem and treating the infection would become an integral part of the management of the situation,” Dr Matambo says. This could involve either stopping labour or an early delivery.