Use of Saline or Heparin Locks for Mothers in Labor

A mother is waiting for cesarean section at hospital.
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When you arrive at the hospital in labor, your doctor or midwife will get you prepared for delivery. Many events in the process are experienced by nearly all women who give birth in a hospital.

Even when an intervention is considered routine or "the norm," you should still learn about it and understand what your rights as a patient are.

One such intervention you may encounter is the placement of a saline or heparin lock. Here's an overview of why it might be needed and what it feels like.

What a Saline or Heparin Lock Does

The saline or heparin lock is a type of venous access. It is more commonly known as an IV or an intravenous catheter. Saline locks are routinely used for most women when they are admitted to the hospital in labor.

Having this IV or saline lock in place allows for immediate access to your vein. This access may be necessary for many reasons when you are in labor, including:

  • To deliver intravenous fluids before you have an epidural or to help treat abnormal changes in the fetal heartbeat
  • To deliver IV pain medications
  • To deliver antibiotics if you are a group B strep (GBS) carrier or develop a fever in labor
  • If you need to have an urgent cesarean section during labor

Perhaps the most compelling reason for a saline lock is in the possibility of heavy bleeding during the third stage of labor (the time between delivery of the baby and delivery of the placenta).

During this stage of labor and immediately after delivery of the placenta is the most common time to develop a postpartum hemorrhage. With the changes that happen in your body when you start to have a rapid loss of blood, starting an IV when you are already bleeding can be very difficult, if not impossible.

How a Saline or Heparin Lock Is Administered

When starting a saline lock, the nurse will look at your hand, wrist, and arms to find the best vein. Don't hesitate to speak up if you know what works well from previous experience receiving an IV.

After choosing a vein, the area of skin will be cleaned. The nurse will be wearing gloves to protect you from germs and to prevent your blood from touching them.

Next, your nurse will put a tourniquet on. Then, a small puncture will be made with a needle. When the needle is removed, it leaves a tube called a catheter that is very small and flexible. This will be securely taped in place. You'll be able to move your arm, and the IV should not cause any pain. 

Saline or Heparin Lock Considerations 

A saline lock can be converted to a full-scale IV at any point, such as if a mother requests an epidural or is in need of IV medication or fluids.

Talk to your doctor or midwife before your labor starts to clarify how they use saline IV locks and express your preferences.

The benefit of a saline lock is that it provides immediate access in the case of emergency, but it really doesn't get in your way during labor. You still can move around without difficulty and even get in the shower or a jacuzzi tub.

If they are placed in the back of the hand, the saline lock can sometimes make it more difficult to get into different positions during labor. Some women ask for the saline lock to be placed somewhere that will let them bend their hands a bit more easily.

The placement will depend on your preference as well as the location of your veins. Sometimes, you will need to have an IV placed in a spot that isn't necessarily your preference simply because of your anatomy. 

By Robin Elise Weiss, PhD, MPH
Robin Elise Weiss, PhD, MPH is a professor, author, childbirth and postpartum educator, certified doula, and lactation counselor.