ninsintyuu ha sake wo nomanai.

A natural reading is:

にんしんちゅう は さけ を のまない。

A few notes:

• 妊娠中 = にんしんちゅう
• は is written は but pronounced わ
• 酒 = さけ
• を is usually pronounced お
• 飲まない = のまない

So the whole sentence sounds like:

にんしんちゅう は さけ を のまない。

妊娠中 means during pregnancy or while pregnant.

It is made of:

• 妊娠 = pregnancy
• 中 = middle / during / in the course of

So 妊娠中 literally means something like in the middle of pregnancy, but in natural English it is usually during pregnancy or while pregnant.

Here, は marks 妊娠中 as the topic.

So the sentence is structured like:

• 妊娠中は = as for during pregnancy
• 酒を飲まない = (one/I/she) does not drink alcohol

This gives a sense like:

• During pregnancy, ...
• When pregnant, ...

The は can also suggest contrast with other times, even if only lightly. For example, it can imply:

• During pregnancy, I don’t drink alcohol
  maybe unlike other times.

Japanese often leaves out the subject when it is clear from context or not important.

So 妊娠中は酒を飲まない could mean different things depending on the situation:

• I don’t drink alcohol during pregnancy
• She doesn’t drink alcohol during pregnancy
• One should not drink alcohol during pregnancy
• People don’t drink alcohol during pregnancy

Japanese does this very often. The listener usually figures out the subject from context.

In this sentence, 酒 means alcohol or alcoholic drinks in general.

Even though 酒 can sometimes refer specifically to Japanese rice wine in some contexts, here it means alcohol broadly, because of the meaning of the sentence.

So here it is better understood as:

• alcohol
• alcoholic beverages

not just one particular drink.

Both are possible, but they sound a little different.

• 酒 is more plain and neutral
• お酒 is more polite or everyday-friendly

In a simple statement, rule, or health-related sentence, 酒 is perfectly natural.
If you said 妊娠中はお酒を飲まない, that would also be natural, just a bit softer or more polite in feel.

So the difference is not about meaning so much as tone.

を marks the direct object of the verb.

Here:

• 酒を飲む = to drink alcohol

So 酒 is the thing being drunk, and を shows that relationship.

This is one of the most basic and common uses of を in Japanese.

飲まない is the plain negative non-past form of 飲む.

• 飲む = drink
• 飲まない = do not drink / will not drink

In Japanese, the non-past can cover both present and future meanings, depending on context.

So 飲まない here can mean:

• doesn’t drink
• won’t drink
• does not drink as a rule

Because this sentence is about a general situation, it feels like a habitual or rule-like statement.

Grammatically, it is a statement, not a direct command.

It literally says that during pregnancy, alcohol is not drunk. Depending on context, that can sound like:

• a personal habit: I don’t drink during pregnancy
• a general rule: People do not drink during pregnancy
• advice stated plainly: You don’t drink during pregnancy

If you wanted a more direct instruction, Japanese might use something like:

• 妊娠中は酒を飲まないでください。 = Please do not drink alcohol during pregnancy
• 妊娠中は酒を飲んではいけません。 = You must not drink alcohol during pregnancy

So the original sentence is not an imperative, but it can still sound rule-like.

Because 妊娠中 already works very naturally as a time expression, and here it is being marked as the topic with は.

So:

• 妊娠中は = during pregnancy, ... / as for during pregnancy, ...

If you use に, the nuance changes a little. Very roughly:

• 妊娠中は酒を飲まない
  = During pregnancy, (I/one) do not drink alcohol
  This sounds like a general rule or habit for that whole period.

• 妊娠中に酒を飲まない
  is less natural by itself for this meaning, because に can feel more like pointing to a specific time point or occurrence within that period.

So 妊娠中は is the natural choice here.

By itself, it does not force one single interpretation. It depends on context.

It could be:

• I don’t drink alcohol during pregnancy
• She doesn’t drink alcohol during pregnancy
• One does not drink alcohol during pregnancy

That is very normal in Japanese. The sentence is somewhat broad and context-dependent.

If the speaker wanted to make it clearly personal, they might add something like:

• 私は妊娠中は酒を飲まない。 = I don’t drink alcohol during pregnancy

If they wanted to make it clearly general advice or policy, they might use a stronger expression.

Yes.

• 飲まない = plain style
• 飲みません = polite style

So:

• 妊娠中は酒を飲まない。
  plain, casual, dictionary-style, or statement style

• 妊娠中は酒を飲みません。
  polite

The meaning is basically the same. The difference is the level of politeness and style.

The most neutral order is:

妊娠中は 酒を 飲まない。

That is:

• time/topic
• object
• verb

Japanese word order is somewhat flexible, but the verb normally comes at the end. Other orders are possible if you want different emphasis, but this sentence is the standard and natural way to say it.

So for a learner, this is a good basic pattern to remember:

[time/topic] は [object] を [verb]

Japanese nouns usually do not show singular/plural the way English does.

So 酒 here does not mean specifically:

• one alcoholic drink
• multiple alcoholic drinks

It simply means alcohol as a category.

Japanese often leaves number unspecified unless it is important. In this sentence, the exact number does not matter; the point is alcohol in general.