Do Cockroaches Lay Eggs When Killed?

David Floyd:

David Floyd has 20 years of experience working as a pest control technician as well as running his own pest control company. David is Quality Pro certified and is a certified Structural Pest Control Operator in the state of North Carolina, and the owner of NCPestControlExperts pest control company.

Contrary to the popular opinion that squashing a cockroach would lead to a spread of its eggs- and ultimately a bigger case of infestation. But that leads us to break down if this is fact or fiction, do cockroaches lay eggs when killed?

do cockroaches lay eggs when killed

It is only in rare cases that mature nymphs make it out of the egg sac alive even without their mother. To avoid that, ways of getting rid of them must be carefully considered. At best, it is advised to call an exterminator for cases of large infestation.

Do Cockroaches Lay Eggs When Killed?

No, cockroaches won’t lay eggs after they’ve been killed, as long as they’ve been properly killed. If you squish roaches or use an appropriate insecticide, it will kill they eggs in the egg sac, and prevent the eggs from being laid. That being said, if you simply squish the mother, but don’t squish the egg sac, then the eggs can still hatch!

If we assume that the cockroach eggs don’t get squashed or poisoned together with their mother, chances are they were not mature enough to hatch to begin with. So in this case, the eggs die as well without the nourishment from their mother.

Even if she “senses” death coming as myths often speculate, the mother is unlikely to risk the lives of her babies by just laying the egg sac anywhere regardless of the situation.

Oftentimes, insecticides are unlikely to harm the cockroach eggs because they are cased in a tube known as ootheca. The ootheca is made up of hard materials that protects the eggs from entry of foreign bodies. But unfortunately, the eggs are still likely to die shortly after their mother.

If the nymphs manage to hatch without encountering any danger around, you are likely to face another level of infestation. Hence the need to seek additional methods of eliminating the eggs after taking care of the pregnant mother.

With that said, cockroaches cannot lay eggs when killed or in the process of dying.

What Does A Pregnant Cockroach Look Like?

A pregnant cockroach has a brown tubular sac protruding from her lower behind. This sac can contain up to 40 eggs. The protrusion extends further as more eggs develop inside it.

American and German cockroach egg sacs are approximately a third of an inch long (8 millimeters), while the oriental ones are slightly longer, reaching half an inch (12 millimeters) in length. Brown-banded cockroaches are the shortest. They’re usually less than one-quater of an inch (5 millimeters) long. Different types of roaches look differently.

When it is time for the nymphs to hatch, they leave through a weak point in the ootheca known as the keel. They breath in the air that comes through it and inflate themselves, which causes the egg sac to break open and allows the nymphs to escape.

An empty ootheca tends to resemble one that is full because the nymphs carefully leave through the keel without doing any damage to the sac. It closes again after the nymphs are gone, which makes it retain its full look.

American cockroaches usually lay smaller egg sacs compared to German ones despite their larger body size. Also, German cockroaches’ egg sacs are often not as outward and exposed as German cockroaches’.

Some female cockroaches can carry their eggs on their bodies through all stages of reproduction until they become nymphs. They are thus known as oviparous insects.

Do Cockroaches Die After Laying Eggs

That’s a no. On an interval of 4-5 weeks, one female cockroach can infact reproduce up to 13 more times, with each egg sac containing up to 40 eggs, thereby producing more than 400 offsprings in her entire cockroach lifetime.

The German cockroach tend to carry her egg sac all through gestation and incubation, until they eventually hatch. She does this to protect her babies from any harm. The average gestation period is one month.

American, brown-banded and oriental cockroaches on the other hand find safe spots to lay their eggs a few days after the sac forms. It then awaits incubation which ranges from 50 to 60 days.

How To Kill Pregnant Cockroaches

Killing just a few pregnant cockroaches can avoid a bigger case of infestation in your home. But, your best bet at doing so is to use the quickest method available. Avoid using baits for pregnant females because they often take a longer time to work, which gives them time to safely lay their eggs somewhere before they die. Check out our guide on what gets rid of roaches!

The best methods you can use include:


It is highly unlikely for the eggs to survive when properly squashed. However, this method will require a considerable amount of force as cockroaches can withstand up to 900 times their body weight due to the presence of hard exoskeleton. It is made up of chitin which is a hard substance similar to keratin found in our fingernails. Another downside is that you have to actually see and mechanically handle the cockroaches, which may not be easy if infestation is large, or if they hide in inaccessible places.


Many insecticides for getting rid of cockroaches are out in the market. However, to hoose the right type that will tackle your cockroach problem, you’ll first need to know how each works.

Pyrethrins and pyrethroids are the active ingredients in most insecticides. Insecticides kill cockroaches by damaging their central nervous system which results in paralysis, starvation and ultimately death. It’s for this reason that cockroaches die on their backs, as they lose control of their motor functions and are thrown off balance.

Glue strips

These are sheets that are covered in a sticky substance that can trap cockroaches and other kinds of bugs. Glue strips are highly safe and effective, as they are non-toxic, and can quickly catch cockroaches within 24 hours. However, for larger infestations, it is advisable to opt for other methods of elimination, as glue strips are effective for only small infestation cases.

Diatomaceous Earth

Sprinkle it on the surface that the cockroaches are likely to run across. Diatomaceous earth works as a desiccant which first destroys the exoskeleton upon contact before drying out its insides.

Diatomaceous earth is abrasive and can break down the chitin of cockroaches’ exoskeleton. When cockroaches walk through diatomaceous earth, they take away some of it that cling to the hairs on their limbs. They typically die later as a result.

Boric Acid

it works similarly to diatomaceous earth. Boric acid usually comes in gel or powder forms, which when applied clings to the cockroach’s body as it walls through the treated area. The chemical attacks the central nervous system of the cockroach which paralyzes and then ultimately kills it and its eggs.

To use, simply sprinkle some powder on the surfaces and corners known to harbor cockroaches.

If you still see cockroaches after you think you have eliminated them:

  • The eggs were probably not crushed

Cockroaches have an exoskeleton that protects the soft tissues of their bodies and the egg sack their females carry when pregnant. If the proper amount of force is not applied when killing it, the eggs (sometimes the mother too) may still survive.

When compressed, a cockroach can endure up to 900 times its body weight in force before it experiences an injury. This is because cockroaches’ exoskeleton is made of a hard substance called chitin which protects it from external harm. However, a strong squash can destroy not only the cockroach but also a pregnant female’s egg sac.

  • Insecticides did not have direct contact with the cockroaches

Most pesticides work by destroying the internal tissues of the cockroaches. However, without directly touching it’s body, the pesticide will be unable to have access to its insides, let alone destroy it.

It is for similar reasons that exterminators do multiple visits before they can declare you house bug-free. Research has also shown that cockroaches have gained resistance to some insecticides such as pyrethrins. If you notice a sudden recurrence of cockroaches in your home, do not hesitate to call bug-control.

Final Thoughts On Roaches Laying Eggs After Dying

Cockroach eggs can still survive even if their mother happens to die before they hatch. This can happen if she dies through a non-chemical process (e.g squishing), when the unaffected eggs mature enough to hatch into nymphs. If the eggs are not fully developed yet, they starve and die without ever hatching. So if you’re wondering do cockroaches lay eggs when killed, it’s technically possible!

Some female cockroaches carry these eggs in a capsule on the lower part of their bodies until the get hatched. While others hide the eggs in warm areas where they can incubate. To avoid the risk of having up to 40 more cockroaches, crush, poison, or contain the pregnant mother immediately.

If you prefer to squash the cockroaches that you see around rather than applying pesticides, be sure to do it very well. This is because cockroaches have a hard exoskeleton made of keratin which protects their soft tissues from being damaged. If not properly squished, your home faces chance of having a bigger infestation if eggs survive.

If you squish the cockroach, the eggs are unlikely to survive. And as long as you properly clean up the mess, you are 100% sure that your home is safe from any further infestation growth.

Insecticides, work just fine too. But ensure that you apply it where you usually see them come out from. Boric acid, diatomaceous earth and glue strips are other cost effective ways of dealing with cockroaches. However, if they are ever overbearing to handle, do not hesitate to call for professional help.

I hope this guide of do cockroaches lay eggs when killed has been helpful and informative!


Leave a Comment