Why Benchtop Incubators are better for Embryo Growth.
July 20, 2023

Saiprasad Gundeti, Chief Embryologist, Malpani Infertility Clinic Pvt. Ltd.

Incubators have a critical role in providing a stable environment for optimal embryo development within the in vitro fertilization (IVF) laboratory. That’s the reason, the incubator is called the Heart of the IVF Lab.

It is critical to provide an in vitro Environment optimized for Embryo Development to maximize the chances of Success in IVF. Good-quality embryos have a higher chance of implanting after the transfer. Optimal Culture conditions ensure better Blastocyst conversion and Quality for successful implantation in the uterus post Embryo transfer. Most good clinics do only Day 5 (blastocyst) transfers today because the success rates are higher with this, as compared to Day 3.

The incubator provides an ideal environment for Embryos:

Temperature : It is well known that temperature can impact various aspects of gamete and embryo function. The incubator should maintain a constant temperature of 37 Deg. Celsius to mimic the body temperature. Cooling of embryos can cause them to die, or slow down their growth. A high temperature also can kill them.

pH : Embryos require a specific pH. for optimal growth. The standard pH range for embryo culture is between 7.2 to 7.4 which is achieved with 5-6% CO2 concentration.

Humidity : Incubators regulate humidity to avoid media evaporation during culture to avoid harmful rises in medium osmolality that can compromise embryo development. Typically, humidity is maintained between 70-80%.

Quality Control procedures include regular checking and calibration of Temperature, pH, and CO2 Concentration to make sure we provide an optimal environment for your precious embryos throughout their stay in the IVF lab. This is why having a full-time embryologist is so important – so he can keep an eye on the incubator in which your embryos are growing.

There are 2 types of Incubators which are used in IVF Labs for Embryo Culture.

  1. Box Incubator is a big Incubator with single gas Co2 gas and temperature control.
  2. Benchtop Incubator is a compact Tri-gas incubator.

IVF labs should have both Incubators. but while the culture medium is equilibrated in the box incubators, only the Benchtop Incubators are used for Embryo Culture.

There are lots of advantages to using Benchtop Incubators for Embryo culture instead of Box incubators. Some of the Advantages of Benchtop Incubator over Box Incubator Includes -

1 Benchtop Incubators have multiple chambers with separate lids which provide ease of culturing different dishes in different chambers, which provides an undisturbed embryo -culture system even when one chamber is opened for handling the dishes/ checking the embryo. Your embryos have their own special chamber ! Box Incubators may have separate shelves, but they have only one door. When we open the door, CO2 levels drop in the whole incubator. So, although we keep dishes on separate shelves, the CO2 level in all the dishes drops, which disturbs the culture conditions and might affect the embryo growth.
2 Benchtop Incubators take less time for recovery of gases and temperature because they are smaller. This allows culture conditions to remain stable for much longer. Box Incubators take much longer for recovery of the gas concentration and Temperature, which leads to variation of culture conditions which can affect embryo growth.
3 Tri-Gas system- with lower oxygen concentration of 5% gives a better environment for embryo growth, better Blastocyst conversion rates and hence better success rates. Box incubators usually expose embryos to air and CO2 gas. The O2 concentration is higher (20%), and this is not good for the embryos
4 Decontamination takes a few minutes because of the compact size and convenience of handling. Decontamination cycle takes 24-48 hours.
5 Since premixed Tri-gas is used, Calibration is not required. Only temperature is measured regularly and calibrated if required. Both CO2 and Temperature need to be measured regularly and calibrated if required.
6 Compact size. Can be accommodated anywhere in the IVF Lab Big Incubator occupies more space.

The Benchtop incubator is far better than a Box CO2 Incubator for culturing Embryos. So, when a patient goes to an IVF Specialist for IVF treatment, you should ask if they have a Benchtop Incubator in their IVF Lab.

Authored by : Dr Aniruddha Malpani, MD and reviewed by Dr Anjali Malpani.